I both enjoyed this and didn't at the same time. Mostly enjoyed, but Valerie was a bit too selfish and whiny for my taste. I mostly tolerated her because the story WAY over punishes her, and that evokes sympathy. Yet still... each time something happened I couldn't help but bang my head against a wall because I knew she'd be going on and on and on about it afterwards. There are a lot of downs and few ups to contrast them. When things are so consistently morbid, I shut off my emotions because -you know- pain is not a fun thing to feel. You need to catch me off guard - make me smile before you attempt to rip out my heart, you know? I'm not saying that a story about a school shooting has to make me laugh out loud ...but it certainly should make me feel something. 
 ...Well, something more than "omg the background characters are so over the top dramatic that I can't stand any of them beyond the therapist" (who happens to horrible name. Dr. Hieler ...get it? Cuz he heals?? Oh, and Mr. Angerson ...because he's angry! *giant eye roll*) 
 Actually, the only other character I liked was Jessica. 
 Two is not a strong number. 
 Still a decent story. And I never reached a point where I hated Valerie or anything. The motive behind the book is more important than my irritation. Serious topics like this need to be tackled and not glorified. It's brave and bold. 
 So I'd still recommend this novel, but with a warning that you wont have that happy "I just finished an awesome book" feel afterwards.