I was reading Dear Abby and someone wrote in about a guy who was 17 and had a gf who was about 15. He turned 18 and the parents of the girl turned him in for statutory rape. According to the story, wherever he goes now he will have to register as a sex offender. It seems his past will follow him around and be a significant part of defining who he is.
I think faults can have a bigger effect on who you are no matter when they happen. Past mistakes can follow you around for a long time, whereas good you have done in the past can be completely engulfed or ignored because of a present fault.