You're not wrong.
I've felt increasingly like this during my 40s and although I still love life at 45, the things I think about and that are concerns are nothing compared to when I was younger.
In some ways it's freeing as I care less about being attractive, (but am acutely aware of the aging process and hate it) and I love my early to bed early to rise routine and would really struggle to go on a night out. Nothing about that would be appealing to me.
And I'm much more cautious and I have an anxiety disorder anyway but that's been present for decades but there are things I definitely wouldn't have been anxious about when younger but am now.
It's an increasing awareness of time, ageing and mortality I think. I wouldn't be eyeing up a sexy young waiter in a Greek taverna anymore as that wouldn't appeal but also can feel a bit sad at the knowledge a sexy young waiter likely sees me as a middle aged woman who's the same age as his Mum and not someone he'd ever see as attractive.
There's something carefree and less self-conscious about being young. I do think about my age when I buy clothes for example. And the knowledge that today is probably the best I'm ever going to look as the physical ageing process is pretty inevitable.
And I'm reaching the stage where my parents who are only in their late 60s, are seeming more old and restricted in their activities and so I have to for the first time, think about them dying and what that means.
And I know there's loads of MNetters who'll say their parents in their 60s/70s and beyond are more active than them, running marathons or playing tennis every week. My parents are not. My parents seem very old in their late 60s and that does affect me and my thoughts about my life and the future.