Did you see her bare butt? It doesn't sound like it. Her skin elasticity on her butt will likely be reflective of an older woman.
In a pair of jeans, some older women's butts can look competitive.
It's hard science and biology. It also goes back thousands of years, when keeping the species alive was very important. Men are programmed to be most attracted to a woman's youthfulness and fertility.
A woman's fertility peaks in her late teens and first half of her 20s. That's why women in this age range are the most desirable women.
No, I unfortunately didn't see her bare backside. You're right, it
is possible she has elasticity issues (but no guarantee)
I've been with multiple 50-somethings. I've been with one 60-something. And I've been with many 40-somethings (a decent amount of which were in the 2nd half of their 40s)
(OK, this is hilarious. The coworker I posted about just walked by as I was typing this message

)
Back to my train of thought, I only recall elasticity being an issue with 2 older broads:
A 54 year old I banged when I was in college.
A 65 year old I've been banging since she was 57. Elasticity wasn't an issue with her in the beginning. It only started to become a problem once she reached 63-64 or so.
I suppose you're right about the biological/fertility explanation. It's funny how even a man like you who doesn't want kids is drawn to the most fertile of broads (but yeah, I understand a man's individual preferences won't overpower a biological instinct thousands of years in the making)