There are tons of characters in comics that suddenly age overnight. Sometimes we have in-universe explanations, sometimes we don't. It's particularly common with young characters.

It's happened with Jai and Irey West, Emiko Queen, Chris and Jon Kent, Garth (IMO, anyway), etc. I'd actually argue it happened with Hal, too.

Which ones do you like and dislike most? I accept Garth easily enough, but do feel like he jumped in age for the Teen Titans. I really think the speed-aging works very nicely for Bart, but with that being part of his introduction, I don't know that he really counts. I do not like the speed-aging for Jai and Irey at all (even though it is reasonably connected to Bart's, really). I liked adult Chris, and found him (and his dynamic with Thara) engaging, but the "temporary child" aspect just bugs the heck out of me. Hated the timeskip on Jon.