I remember being obsessed with the Jill and the Pony books as a kid, but, now in my 40s I do wonder what happened to her as she grew up (!). Bearing in mind it was set 1930s or 40s, I imagine she got married off to a mean guy who made her give up Blackboy and she returned to riding aged 40 post divorce and kids and started a livery yard 🤣
Then there's Darrel from Mallory Towers. Totally running a WI group in the 80s and still being "head girl" in all walks of life.
Any others?