I am in my 70s and the only thing I can add to this discussion is that “old age” sort of just creeps up on you.
You don’t know when it starts but at some point you discover you can no longer do things you used to do (like running, or long walks, or working on a project all day). It does not happen all at once. Just little things until you realize you are old. Strange thing to say, but your mind plays tricks on you. I don’t know how long it was before I discovered I was no longer a teenager follow by the discovery I am no longer a middle age man.
I am an old man in an old body. I still walk every day, and still work in my garden but the walks are not as long and my time in the garden is more time resting between doing something.
To be honest I never thought I would live past 18 (Vietnam infantryman) so every year I have had since has been a bonus so I will wear this old body with pride until we move on to the next stage ...
I think we’re in the same club. I’m also in my 70’s, don’t look it, but I am in no way in the same shape as when I was younger. I’m sure as hell not doing 50 pushups, 100 situps, or anything like that every morning. But it came to me slowly. I’m still more active than many 50 year old men and even the 40 year old couch potato that’s glued to the tv all day.