As a twenty something dude who got Facebook in highschool, I can already feel its effect. My earliest pictures and posts don't reflect who I am at all now and I often think about deleting my account just to get a clean slate.
It's a similar feeling to having friends from childhood. They know all the stupid shit you did and they bring it up from time to time. The difference is that that stupid shit is recorded for almost anyone to see and reference whenever they want.