i found i enjoyed my 30's a lot more than my 20's... you really start to know yourself and your identity and relax about things a lot more 
How old are you now ? 50 ?

Re age.. it all depends on your certain lifestyle. A lot of my close friends are settled down married and do fack all..
Bollox to that - for me been out in the clubs all the time keeps me feeling young, and my GF is only 22 also so im still very much in the fold

..
im gonna go with Chuff on this, just live each day as it comes and dont worry so much