Why do teens have to die so young?

i was just told one of my friends died she was only 15. someone plz plz tell me why they have to be so young when they still have so much to look forward to. and im sure yall r thinkin she died in a car accident and that was not how it was that she rejected the final heart they gave her. she had had at least 8 different ones. why did she have to die now and she was a christan to.