"You either die a hero or you live long enough to see yourself become a villain!"

This infamous quote from Harvey Dent in The Dark Knight has been bothering me whole day. Is this really true? I consider this quote, one of the best quotes of all time. People change and from time to time they are good, but sometimes they are bad. So is the choice really up to us, will we become heroes either villains? We change from time to time and we never know when will we die, or how, or will we die as heroes, or as villains. The choice isn't really up to us, its what "God" wants it to be, or simply destiny.

I want to know your thoughts in comment. Help me with this one!