Notes from a card carrying septuagenarian:
1) The comics.
When the comic "Little Orphan Annie" was still being produced by its originator, Harold Gray, and it reached its fortieth year of publication, the question arose of how Annie could have had forty years of adventures and still be merely a child. The key was that Annie's birth date was February 29th. Thus, with Annie having had only had ten birthdays, she could justifiably be presented as being only ten years of age.
The comic "Archie" was introduced by cartoonist Bob Montana in the year, I believe, of 1943. If all of the teenagers were then sixteen years old, their birth year would have been 1927. Therefore, all of those teenagers, Archie, Veronica, Betty, Reggie, Jughead, Moose and Midge would all today be more than ninety years of age. How old the adults Mr. Lodge, Miss Grundy, Mr. Flutesnoot, Mr. Weatherbee, Miss Beazley and Mr. Svenson might be is left as an exercise for the student but they all wear their ages well, don't they.
Similarly, in "Dennis the Menace", the little boy Dennis Mitchell first appeared on the scene in 1951 at the age of five which would lead to a birth year of 1946 and a present day age of more than seventy. Ditto, I think, for Charlie Brown of "Peanuts" fame.
Maybe my dates are off a little bit, but not by that much. Except for "Gasoline Alley" and "Doonesbury", cartoon characters do not seem to age. We must, of course, acknowledge the character age reset that took place a few years ago in "For Better or For Worse".
2) On radio.
A good many years ago, Garrison Keillor told a Lake Wobegon story about a quack medicine that was said to reverse the effects of aging. It wouldn't actually make you any younger, but the effects of aging that occur in so many cases would be reversed. The medicine was called "Compousine" and there was its derivative "Limousine". When the fakery was revealed, several townsfolk who had used the stuff and who said they felt better sadly came to realize that they couldn't get any more of it.
3) On television.
The collie dog "Lassie" was on CBS television for twenty years, from 1954 - 1974. A succession of animals made that canine's geriatricity possible. However, the character of Jeff Miller played by Tommy Rettig aged out of the series to be replaced by the younger character of Timmy Martin played by Jon Provost. Similarly, the television version of Dennis The Menace was played by Jay North for four years, from 1959 - 1963 before he aged out of that role.
There are other entertainment examples connected with aging as well, but as those of us who live in a linear temporal environment (never mind Mr. Einstein) simply get older, we live out lives as best we can (hopefully) and we should be content with that.