When I was around 22 I was in the best shape of my life. Assuming that the prompt means going back to the same state, I'd take it with no hesitation. It was before I damaged both my shoulders and started putting on weight, and it was before the chronic illness I have had shown itself and caused a lot more problems for me.
If it means that my body is reverted and not my mind, I could go to see my doctor and make sure that none of the damage happens, and be in a much better condition than I am now.
That was how old I was just before my metabolism slowed down, my muscles gave up and waved a little white flag, and without any warning at all, I was suddenly a fat bastard.
I'd wanna go back to 22, currently almost 30. I developed a lot of health complications around 23-24, and 22 is the last time I remember my body not being in constant pain.
It's not actively hurting me, but I don't have full range of motion when grabbing things, my grip strength is way down, and it does hurt sometimes. It's like an 80% it's OK, 20% it sucks kinda bad type thing.
I am not a follower of Islam, but I have read some of the materials, and they said that in heaven everyone will be 30 years old.
That seems like a pretty decent age. Like you're old enough to be an adult at 30, but you're still young enough to be able to enjoy life if you didn't have soul-crushing work to do.
It's possible I haven't reached it yet, being in my late 20's. At least after the rest of my chest hair grew in sometime in the early 20's. Furry nipples on a bare chest looks really dumb.
I actually think it would be cool to be in your 70s - you can still do most things and can mostly think straight but other people think you cannot and so they don't bother pestering you.