ALLENDALE, MI -- Trayvon Martin had an average American family upbringing in southern Florida. He had his faults, but was no criminal, his mother said.

Still today, Sybrina Fulton tries to reconcile the memories she has of her son with his death by gunfire in a gated community, as he walked to his father's home from a nearby convenience store.

Days before his 2012 death she had been horseback riding with him to celebrate both of their February birthdays.

"What could have been to cause my son to lose his life," Fulton said to thousands gathered at Grand Valley State University's fieldhouse Monday, Jan. 19. "The very thing that caused my son to lose his life was the color of his skin."

News of Trayvon's death spread around the world. The 17-year-old had been on the phone with his girlfriend when he was approached and eventually shot by George Zimmerman, a neighborhood watchman.

Zimmerman suffered injuries that day-- a fractured nose, two black eyes and lacerations on the back of his head. He claimed self-defense in the shooting and was later found not guilty in July 2013 by a Florida jury.

Since that day, Trayvon's mother, Fulton, has taken up public speaking around the country in her son's name and in honor of all those who have fallen victim to senseless gun violence, she said.

Fulton spoke before thousands of people on GVSU's Allendale campus Monday and is slated to speak at Grand Rapids Community College's Ford Fieldhouse later in the day. On Tuesday, she will speak at 10 a.m. at Davenport University's Sneden Center Auditorium.

She shared a message that America cannot simply sit back as more young people die because of gun violence.

Profiling in all its forms — by race, gender or religion - is not acceptable and is discrimination, Fulton said.

This discrimination happens all over America today, she said, and whether news of gun violence is nearby or far away, it cannot be ignored.

"It hurts my heart to see what happens. People sit back and say, 'not my community,' Fulton said. "What happened to Trayvon we don't want to happen to any more of our children."

Trayvon, she said, was a teen who enjoyed the same things many other teens do, visiting the mall, buying fancy sneakers and sporting a nice haircut.

Lives have been cut short through gun violence at Sandy Hook Elementary, in Aurora, Colo., in countless places across the United States. It's not just the immediate families of those lost that are impacted. It's the co-workers, the classmates, the entire community and beyond, Fulton said.

"If you have a heart that's sitting inside of your chest you cannot allow it to continue to happen," she said.

She called on those in attendance at GVSU to stand up against violence by pouring their hearts into something positive. Find a community nonprofit that works for the greater good and get involved, give back and make a difference, Fulton said.

The message was one that resonated with many students in attendance.

Dustan Luban, a GVSU senior, acknowledged that Trayvon was an average teen, a fact that resonated with him the most after hearing news of the shooting.

Reese Drilling, a visiting high school sophomore, felt called to teamwork and community action.

"It's not about individuality but about unity, working together," he said.