As I get older my perception of this changes. Ask me this question when I'm 10 I would of told you 29. Now that I'm 29 I think 79. When I'm 79 I'll think 109. Life goes too quickly. We are all young at heart, its just the body that ages around us.
i am in my thirties now, i am happy generally, and i feel younger now than when i was both 21(going through a bereavement) & 29 (traumatised by the thought of turning 30).... so i think happy people seem young, and misery makes u feel & look old...