Ninety year old people improve with strength training.
People who started late in life can dramatically progress their athleticism.
There are 101 year old marathon runners.
There is a 91 year old female gymnast who can do movements some of the strongest Crossfit competitors in the world can't do yet.
Look up pretty much any search string on sprinting, cognitive sharpness and nonagenarians, centenarians and supercentenarians; and you will find examples of people who do not just rapidly deteriorate as a result of minutes ticking by. The conventional modern thinking on what it means to age is unsupported by any actual scientific evidence. In logic, all you require to utterly destroy a proposed rule is a single counterexample. We have not one, but many.
Age is B.S.