Guess, it depends how one handles stress of parenting and one's personality temperment. Generally speaking I do notice those who try to be more physically active for several years before and after pregnancy, it seems to help them, as well as for the long term. Frankly I'm just impressed by the level energy required to be a parent for more than 1 young child especially as one ages.

What is the age gap betwee you and SO, indy?
Mine is 16 yrs....but he tends to hang around fairly active (cycling) folks around his age. So I genuinely have a warped sense of what 69 looks like. He has 2 young grandchildren.

The only thing that I even share remotely with any 53 yr. grandmother, is that my eldest niece is 26 yrs. old. (From a sister 1 yr. younger than I.) She is the eldest of the whole bunch of nieces and nephews..with the youngest nearly 3 yrs. old. My youngest sister had her first child at 40.

It is a large age range, but kind of neat to see of them interact among one another, within 1 generation.