I have a strange relationship with this thought. I grew up hanging around kids who were much older than me, and I looked a lot older than I was, so I didn't have that period a lot of kids do where they think 25 or 30 is old.

Also, my parents had me later than is typical (Mom was 35, Dad was 40), so they were in their 50s when I was a teen, and that just seemed like normal adult age to me.

If you had asked me at what age I considered someone to be old, I probably would have said around 60 for most of my life. I'm in my early 60s now, and I can't decide if I feel differently about it. I don't really have a problem considering myself old: my kids are adults, I'm getting ready to retire, etc. On the other hand, it feels like there's a huge difference between 60s old and 70s or 80s old.

Oh, and though my opinions on a lot of things have evolved over the decades, I don't feel different mentally (I don't just mean sharpness, but the way I approach things and my outlook). But my back is stiff if I sit for too long.

I don't think I'm representative though.