Is this a good novel concept?

It seems like a interesting story. You said the friend died in a shooting and that intrigues me. I was wondering, mostly out of curiosity, if the main character knows why or who killed the girl. You might already planned it out, but if not, it would be neat to read if perhaps she didn't know who did it or exactly why. Although, you could be going for more of how her life was effected by the death of her friend, which is also cool. Either way it sounds good. :)