When I was a kid and read the comics, Jimmy was a guy who was much shorter than Superman/Clark Kent, and Jimmy also had red hair, in stark contrast to Superman's black (or blue????
) hair. Jimmy also looked pretty much like a kid, at least sometimes, although I could never get used to comic book Jimmy's slicked-back hair and weird way of dressing. What kid would look like that?
As for comic book Jimmy's age, he often seemed to be about the same age as Batman's Robin, and Batman's Robin seemed to be about fifteen or even younger in the Silver Age comic books that I grew up with. So if Jimmy is more or less the same age as fifteen-year-old Robin, Jimmy can't be more than eighteen himself, and he might well be younger.
But anyway, because I expect Jimmy to be rather short, red-haired and young-looking, I could never accept Michael Landes' tall frame, dark hair and comparatively mature look. No way he looked like Jimmy Olsen! So I was glad when they replaced him, although it's a pity that they didn't get Justin Whalin from the beginning. If you think that Lois Lane's haircut was startling, what about Jimmy's total metamorphosis?
Ann