Well, my TBI was at age 18, but oddly enough I very much wonder how much the injury changed my personality (and it is a question of how much, not if). I've been described by others as having almost 2 personalities, diametric opposites, it seems. One angry, demanding, and bitter, the other calm, accomodating, and non-judgmental. I have huge problems with anger.

Age 18 is till young in a person's life, and I don't think their personality is fully formed yet. I truly wonder how things would have been had the accident not happened.