<human>: Give me the gist of the text in a nutshell

I'm kinda freaking out right now. She got really offended when one of my buddies was talking about how crazy a person must be to shoot up a school. I asked her why, and she went on a huge rant about not every school shooter is insane and some have legitimate reasons and are just going about it the wrong way. We got into a huge fight because I didn't see her point of view, when she finally screamed at me that she had almost been a school shooter. 

I knew she was bullied a lot, but I had no idea it had affected her so much until this fight. She said the only thing that stopped her was some guy that asked her if she was okay when she was crying in the stairwell about to go on a fucking rampage. 

I'm really confused right now. I know as her boyfriend I should support her, but to me this just seems batshit crazy. I don't know if she could get in trouble for having almost killed a bunch of kids, and I really don't want to be involved with her in case she gets unstable again and shoots me or something. But I know how hard it must have been for her to tell me, and I don't want to set her off by dumping her.
<bot>: My otherwise normal girlfriend was almost a school shooter, and only decided not to because some guy was nice to her. I'm not sure how to proceed.