years. >> reporter: and in those years, they have turned their pain into action. >> i'm 14. i shouldn't have to think about getting shot in my school. >> reporter: starting a movement against gun violence, that has gone global. with march for our lives. and a crisis that's only gotten worse. there's been more than 150-mass shootings since the beginning of this year. and i am sure, my number is low and outdated. >> yeah, it is. >> people are always saying, if sandy hook didn't change anything, you already know what i'm going to say? >> yeah. i know what you're going to say. and for, like, two years after the shooting, i thought that the reason why these things kept happening is because they just needed to hear one more story. politicians just need to hear one more voice. and so, as a child, i tried to do that. and then, i got older, and i worked more. and i realized, it's not that they don't know what to do. they choose not to. >> reporter: and it isn't just a horrific mass shooting that scarred their high school years. since then, they have been hit by another trauma.