I wish there was signal strong enough irl for people to stop in the middle of a forest and attend their classes irl lolol.
If i had to imagine how they did it pre internet/rotom tech(altho lowkey they alr had advanced enough tech for online classes in the pokemon world... we just didnt imagine the idea of remote classes ig), I'd say they probably just took years off. Sorta like gap years? Since kids would often want the adventuring experience, ppl probably didnt think much of age differences in various classes/grades.

abt the last bit, Ive always thought that was how it was meant to be. of course for people like Ash pokemon battling is their entire life goal, but for the majority of ppl in-universe that's clearly not the case. Even most of Ash's travel companions(or classmates, in SM) only travel temporarily and have different career goals outside of being a league champion. Not to mention it doesn't actually seem to pay anything, u gotta get sponsored the way Leon does.

another thing i notice is that friede(and to some extent the other adults onboard) feel a lot more present as adults. Ash in the early generations of the show did NOT feel like a ten year old, so even tho he was way younger than the adults he travels with it never rlly felt like there was a difference in maturity or responsibility.