Parkland, Florida (CNN) Lina Crisostomo's SATs are coming up next week, but college test prep has taken a backseat to funerals, vigils and walkouts.

It's been like that since a gunman stormed Marjory Stoneman Douglas High School, killing 17 people and sending Lina running from campus.

"Homework doesn't really seem that important now," she said Friday, the day before her 17th birthday. "My attention has changed to fighting for these 17 lives."

Lina is one of many Stoneman Douglas students who's been channeling grief into fighting the gun lobby since the February 14 shooting in Parkland, Florida. In little more than a week, the student-led movement made gains no one predicted, not even the students. Now, with classes set to resume on Wednesday, Lina and others worry about losing momentum.

"I know I have to get back to reality, but it just doesn't seem as important as fighting," she said.

It's not the only thing on students' minds as they prepare to return to the place where their friends and teachers were mercilessly gunned down. While they grapple with balancing school and activism, many are bracing for the emotional toll of confronting memories they'd rather forget.

"I feel like I'm not ready to enter the school, but I also feel like I can't let (gunman) Nikolas Cruz win," said Lina, a junior. "I'm strong enough to enter the school and give comfort to those who can't."

For those who feel invested in the movement, school feels like theater compared to real-life activism. And, for seniors who end classes in May, the question of what's next has implications beyond the final weeks of high school.

'It's really hard to deal with'

This is not the first time a mass shooting has hit close to home for Lina. She lived in Connecticut when a gunman killed 26 people at Sandy Hook Elementary School in 2012. She remembers making cards as a fifth grader for those affected by the shooting. But she said it was too distant from her small world to feel real.

This time, it's different, she said. The Sandy Hook survivors were too young to speak for themselves. Columbine High School students did not have social media, and the shooting preceded the politically charged debate around mass shootings.

The Stoneman Douglas students are old enough to form their own opinions, she said. And, they have the tools of the digital age to help them organize and mobilize.

"For me to feel safe I have to see that we're doing something with gun control," she said. "If this keeps happening and nothing gets done, none of us are safe."

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On Sunday, some students returned to campus for the first time since the shooting, to attend an orientation before classes start. The school is focused on being "flexible and accommodating" as students process their emotions, said Robert W. Runcie, superintendent of Broward County Public Schools.

Members of the Stoneman Douglas Drama Club have been working out those emotions together -- partly through their art. For a town hall that aired on CNN a week after the shooting, members of the group wrote and performed a song about perseverance.

With school closed, the group gathered at a hotel in Coral Springs on Thursday to regroup. Their teacher let a CNN reporter speak to them at the end of the meeting. CNN is not naming them because they're minors.

About a dozen students, ages 14 to 18, sat on the floor of a hotel conference room, leaning against each other with the ease of friends who consider each other family. They were together during the shooting, they said, about 60 students crammed into a closet. Since then, they said they barely spent a day apart.

"We're constantly with each other, so it feels weird when we're not," one student said.

They described memories of the shooting and lingering trauma. One boy expressed surprise at how quickly things changed. One minute, they were rehearsing an upcoming show, "Yo, Vikings," in the drama auditorium. The fire alarm went off and they were making fun of culinary class for presumably setting off the alarm, again. Then, the sound of gunshots sent everyone running to the closet, where they huddled together and sobbed.

Several students left their phones in their bags outside of the closet. One girl said she used a friend's phone to text her parents -- the only number she knew from memory. She wanted to let them know she loved them, but it would not send.

Another boy who left his phone at the school said he was startled to log on to his Snapchat for the first time days after the shooting and see a flood of messages pleading for information.

The sound of a door closing or a phone dropping would take them back to the shooting, they said.

"My brother had a friend over and they were screaming," one girl said. "I had a lot of friends over and all of us just started crying ... it just kind of sent us back."

"You just get so frustrated with yourself because you're like, 'why is this bothering me? This hasn't bothered me before,'" she said.

Another girl recalled freezing in panic when she dropped a metal bottle on the makeup counter at Macy's -- the sound was terrifyingly familiar.

It's easier to talk about the shooting with people who were there, another girl said. You don't have to explain what happened, or deal with well-intentioned apologies and questions.

"Whenever people say, 'Are you OK?' you really don't know how to respond," she said. "You hear a loud noise and then you freak out and they're like, 'What happened?' It's really hard to deal with."

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Deciding between school and activism

Responses to trauma take different forms, and a handful of students are channeling their grief into activism.

In interviews with 12 students, most said their activism was a coping strategy; others called it a response to the reality of what they'd experienced. Whatever the case, it leaves them little time to breathe, let alone sit through hours of school, senior Ryan Deitsch said.

"There's a lot more work to be done, and I just know that if all the students who are active now have to stop, nothing's going to change," Deitsch said in an interview Friday at Pine Trails Park, home to a sprawling memorial to the victims, as well as a Red Cross resource center.

He had just left a Broward County Commission meeting with fellow seniors Diego Pfeiffer and Chris Grady, who said that fighting for gun control felt more urgent than school.

"It's opportunity cost. Our time could be spent so much more valuably," Pfeiffer said. "I want to be there to support my friends, of course, and to support my teachers who are coming back to my scary school, but right now we could be changing the world. That's a little more important."

With no single leader spearheading the movement, Deitsch said the students are taking on different tasks to prepare for a nationwide protest on March 24 dubbed March for our Lives.

What happens after graduation is another question. Grady said he had signed up to join the US Army, "but it just seems like this is just so much more important now."

"The real fight is at home," Deitsch interjected. "Yeah, not abroad. At least for now," Grady said.

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Real-world activism might be more valuable right now than spending hours in an AP government class, Deitsch said. "If we're changing the government we should not have to take a test on the government -- especially when we see how many people have their heads up their asses and are not listening to those who are speaking out to them."

Some adults have offered to assist the teens, but Deitsch and his friends said they're not interested -- not now, at least. Film crews have asked to follow them. Recently, the teens were offered office space in exchange for attending a meeting that turned out to be a photo opportunity, he said. They declined.

"We are not here to make deals. We are here to push forward change and make sure we don't have to watch more people die," he said. "Every time they ask to come into one of our houses to film, that gives away the very few moments we have to breathe."

Those moments are increasingly scarce. A few feet from where they stood, television news crews filmed live shots and interviews. In the other direction, groups of families and friends strolled through a grassy field dotted with colorful shrines to the victims.

Some visitors laid flowers at the altars, each brimming with personal relics: stuffed animals, swim goggles, boxes of pasta. At the memorial's entrance, visitors exchanged stories and helped themselves to donations of food and drinks from local vendors.

A temporary memorial at Pine Trails Park in Parkland, Florida, has become a space for public mourning and healing.

"We're holding each other together," Pfeiffer said. "We're grieving in our own style. We're grieving together and I wouldn't be grieving with anyone else."

His plans after graduation? "Still figuring it out," he said.

Network pundits and political analysts may criticize their brashness, but in at least a dozen conversations with people in Parkland and neighboring Coral Springs, locals said they saw them as heroes.

"This is the same generation that was eating Tide pods," one man remarked at Pine Trails Park. "I was worried about them, but they're really stepping up."

'We are making these politicians look like amateurs'

For each student who has become a familiar face on television news, there are dozens more pounding the pavement. One of them is Stoneman Douglas senior Taryn Hibshman, who organized a rally on Thursday in Boca Raton, about 10 miles from Parkland.

Before the shooting, watching television debates was the extent of her political engagement, she said. Now she says she's committed to fighting for gun control when school resumes and as she heads off to college.

"I'm ready to go back to school and return to normalcy, or find the new normal," she said. "I'm kind of excited to move the movement forward with the rest of the school community."

The rally location was chosen to coincide with a meet-up for @BrianMastFL, who took contributions from the NRA's PAC. #MSD student @tarynsara wants to draw attention to politicians who take money from the NRA #msdstrong #StudentsStandUp pic.twitter.com/4m0pwX5ZWn — Emanuella Grinberg (@grinsli) February 22, 2018

The rally began at a German-style pub in an upscale shopping center where Rep. Brian Mast was scheduled to appear on behalf of Congressional candidate Paul Spain. Mast is one of several Florida lawmakers who has taken money from the NRA, and Hibshman said the rally's goal was to pressure Mast to stop accepting NRA contributions. (The following day, Mast came out with a list of measures he supports .)

A small crowd joined Hibshman and other Stoneman Douglas as they made their way down Federal Highway, waving signs that said #MSDStrong" and "Why is NRA money more important than our lives?" Passing motorists honked their car horns in solidarity and shopkeepers stepped outside to take photos and cheer them on.

They traveled to a small park called the Garden of Humanity, where a statue in the plaza bears the rallying cry of the Stoneman Douglas students: "Never Again."

After a moment of silence in honor of Coach Aaron Feis , whose funeral was taking place at the same time, Hibshman raised a loudspeaker.

"As children, we are making these politicians look like amateurs," she said. "It's because we're not driven by money, we're just trying to stay alive and we have nothing to lose -- no votes, no NRA money and certainly no Congress seats," she said.

A few clips from my speech at yesterday's rally. I, we, will not be silenced. #StudentsStandUp pic.twitter.com/h5H5SzL4KX — Taryn #NeverAgain (@tarynsara) February 24, 2018

After Hibshman, fellow Stoneman Douglas senior Hannah Karcinell, 18, stepped up. The day before, she had attended a funeral for her friend, Nicholas Dworet. The 17-year-old senior was recruited by the University of Indianapolis swim team, and the team's coach spoke at his funeral, Karcinell said.

She said she takes comfort in remembering her last conversation with him about Indianapolis. But his memory lingers in the room of her home where they studied together, and she expects it will at school, too.

"And like all the beautiful dreams

I've had every time I sleep,

I hoped we had more memories,

I wished I had more time

to spend with you."

Endless // ma.c.a pic.twitter.com/EzYUK71FWK — #guncontrolnow (@hanfromtheblock) February 25, 2018

"It will be hard sitting in classrooms with empty seats and thinking about the people who aren't there," she said. "But I think it's important to be with the community and be there for each other."

Before the shooting, she considered a career as a civil rights lawyer. Now, as she looks toward college, she's thinking of switching to political science, she said.

The day after Thursday's rally, Karcinell and her friends joined students from Deerfield Beach High School on a walkout. It was an 11-mile trek to Stoneman Douglas, but adrenaline powered her through it. She knows it sounds crazy, but she thinks part of it was Nick working through her.

As the movement continues, she hopes it stays focused on the victims and fighting for stricter gun control measures. "We can't forget why we're doing this."

'We are going to survive this'

The drama kids have mixed emotions about returning.

It's unclear whether "Yo, Vikings" will run on as planned on March 1 to 3. Meanwhile, they worry about being branded shooting survivors or victims, when all they want is to be called students -- or, even better, talented performers, especially at upcoming competitions.

"Now we're going to be known as the students that go to the school that had the shooting, and it's kind of hard to think about," one said.

"This school has done so many positive things, and we've all come out so great from here -- most of us -- but it feels like this is what we're gonna be known for and that just doesn't feel right," another said.

More than anything, they're looking forward to reuniting with teachers and classmates -- the only people who understand what they're going through.

"It's just hard being alone in a moment like this and you have to talk about it with people. You can't just keep it up inside," one boy said.

As much as she loves her drama family, another girl said she's looking forward to seeing other classmates and hearing their stories.

"It's the feeling that I miss them and I'm not seeing them that makes me want to go back," she said. "And it also feels like when I get back I'll have some sort of closure, like everything is going to be OK. We are going to survive this."