We've talked about ageups, now let's talk about those that get reverted to young over and over or are never allowed to age.
Now, I'm not talking about the general de-agings that affect everyone all at the same time. I'm more about Supergirl - she has various versions, but never seems to get as old as she should, and is reverted to teenhood on many reboots/new iterations. Gar and Raven have been deaged to team up with subsequent Robins (older again, now, though). Jimmy Olsen should be much older than he's frequently depicted - often it seems they won't let him get to "full fledged" adult state of not being "the kid" of the office, respected professional at work, etc. Billy Batson, of course, has been reverted to baseline age a few times, too. I get why with him - the kid-to-adult transformation is a significant part of his mythos.
Anyway, which ones work for you and which ones don't?