Today I have seen a very old lady pushing a buggy with a child of about 18mths - 2yrs in it. There were no other adults anywhere in the vicinity. When I say "too old" I mean this lady looked about 80 (and before you ask, I'm not a 22yr old who thinks 40 is one step from death). In fact, my GM is 92 and this lady didn't look much different from her. She was huffing and puffing as she pushed the buggy up a slight incline. She looked pretty frail TBH.
Accepting that she may well be decades younger than she appeared, what's the Mumsnet opinion - how old is too old?