What would you say about this?

Are most mobsters born into the life or do some guys end up choosing the life later on when they get old enough to decide on what they choose as a profession?

Such as say a guy that hangs out in the city, one day ended up meeting a connected guy, built a friendship, and then ended up showing interest in the mob? Would he have a chance to become a mobster himself? Or would they pretty much ignore him cause he didn't grow up in the life?