"I do have limits, but I also have goals and dreams," Gruber tells PEOPLE

Brandon Gruber’s story could have ended with the bullied senior with Down syndrome being crowned homecoming king last fall, but that was just the beginning. In less than a year, Gruber has taught his high school classmates that he’s much more than his diagnosis.

“It does not define me, or who I am. That is my quote of the day,” Gruber says, laughing.

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“Becoming homecoming king was the happiest thing that ever happened to me. Now I feel like I am a part of my school,” Gruber, 19, of Santa Cruz, California, tells PEOPLE.

Now he wants to pass that feeling along to his peers.

“I wanted to do something that would inspire others and change their lives,” Gruber says. “I used to feel like I was not part of things – that I was isolated and excluded – and I wanted to do something so people felt like they were a part of things.”

After hearing that some members of his class could not afford to go to winter ball, Gruber, who is also a talented artist, decided to sell his note cards through his website 321life to raise money to take 5 boys and girls to the formal dance. The money he earned allowed him to purchase everything from formal wear to dinner and dance tickets.

It was such a success that he decided to do it again for 10 more deserving students for senior prom. The teens were treated to shopping trips for dresses, tuxes and manicures and taken out to dinner.

“We had so much fun shopping! I never thought I was going to go to prom,” says Juana Sanchez, 18. “We went to places we had never been to before, like a really nice Italian place for dinner.”

Ulises Solorio, 17, says he probably wouldn’t have gone to the formal dances if it weren’t for Gruber.

“It’s a lot of money, and I would have used it for something else. It was pretty cool of him. People think about themselves, but Brandon thinks about others,” Solorio says. “I used to judge people by the way they look on the outside, but Brandon taught me not to judge a book by its cover.”

Gruber had a rough start at Aptos High School. He was mainstreamed into classes, but he says most students “called me mean names and they didn t care about me that much.”

His parents were ready to pull him from the school because they felt both the administration and other students had marginalized him. But Gruber was inspired to “blow up” his senior year by joining a variety of clubs on campus and getting noticed by those who had ignored him.

“I decided to get rid of that title of ‘Down syndrome’ and start a new chapter in my life, and when I redefined myself, they started seeing me as a different person.” Gruber says. “Now they think I’m pretty awesome. Being popular to me just means having more friends in your life.

“I do have limits, but I also have goals and dreams,” he adds. “It’s not about Down syndrome, it’s about who you are, not what people think.”

One of the groups he joined is the Migrant Farmworkers Association. Gruber is the only non-Mexican member, but his mother Teresa Gruber’s parents were Japanese-American farm workers interned during World War II.

“You have these stereotypes [of Down syndrome] in your head,” says Selena, 17, one of the students Brandon is sponsoring for the senior prom and a member of the MFA. “Once we got to know him, I thought, ‘You are really insanely smart and you have a vision and just go for it.’ We all feel a little isolated, a little different at school, just like Brandon.”

Gruber quickly found common ground with his new friends.

“I started talking to them about what I thought about things, what I did and what I liked to do,” says Gruber, who is an aspiring model and artist and enjoys traveling with his mom and his dad, Tim Gruber.

“I talked to them about the experiences I had, and they hadn’t had those experiences, so they were interested in hearing about it,” he says. “And we shared about feeling isolated and excluded from things at school, so we had that in common.”

Gruber struck a chord with students who felt like they didn’t fit in, and they rallied to get him elected homecoming king.

His father, a former high school jock, was surprised when his son told him about his nomination.

“When he came home and said he was nominated, we said, ‘Yeah, right.’ Then we checked and [the school] said, ‘Oh, yeah. He’s in the final five,’ ” his father said.

“When he was a freshman, we went to the homecoming game and he said, ‘I’m going to be the king.’ And I never said he couldn’t do it. I just said, ‘Dream big, buddy.’ I always tell him to live loud and dream big,” he added.

In addition to raising money through his own website, the teen was inspired by a childhood friend who had cancer to volunteer to make meals for cancer patients through the Teen Kitchen Project.

As for his advice to others, Gruber says, “Break your shell and meet new people. Other people might not have the support I had. My parents help make my dreams come true. My dad told me no matter what game you play, make sure you are having fun.”