Agreed. Maybe the guilt finally got to her, or the realization that she would be spending the rest of her life in jail if she didn't tell? Who knows what goes on in the minds of teens these days.
Also, I meant she may not have realized this at the time the murder occured. Since she is 15, she may honestly have thought that she would be tried in juvenile court.
Well this is really going to be a bag of worms if there is no DNA evidence at the scene that would point to him. IMO