I'm always confused about how "old" I really am.....

I'm 38 married and I don't have any kids. Though my lifestyle has more in common with younger folks I generally feel much older than them with little else in common. Then again people my own age always seem to feel a whole lot older than me..... Most times I feel like I have the most in common with and relate best to people who are actually a bit older than I am - who maybe had kids, but they are grown up. I feel like I understand that generation (a little older than me, but younger than my parents) a lot better than really young people.

Physically, mentally I think I feel a lot younger than my chronological age. I catch myself thinking I'm not really that old am I often...