I had an issue with my body not producing growth hormone when I was young, and the bones in my face fused when I still looked really young, so for the majority of my life I've looked much younger than I am. I would only half joke that I looked like a 16 year old, and yeah, I would get asked for ID all the time - to the endless amusement of my friends.
However I'm 43 this year and for the last few years I have not been asked for ID at all. While my face still looks young, the cracks are definitely beginning to show, which is great for me after all this time. One man's trash is another man's treasure and all that - some people would give anything to look like a teenager, while I've spent most of my life desperately trying to not look like one. Only in very recent years has that happened.
Physically, of course my knees are shot to shit, but I feel fine. I don't feel like someone who is not that far off from old age - I see people younger than me complaining all the time about their back hurting - mine thankfully isn't, and a friend around the same age says the same, so I have no idea what people are doing to themselves to seemingly have life-long back pain.