>>35590908Being a pokemon trainer is a complete gamble since you lose money every time you lose, which is why shitty or mediocre battlers have real jobs. Traveling is also harder on people who are trying to settle down and have a family, or are just generally older and achier and less physically fit, which is why not everyone grows up to be a pro trainer. Almost all people go on an "adventure" as a coming of age, though. (This does not mean the whole entire region, though it is possible if you are a good trainer, like the MC of every pokemon game.)
That precise "coming of age" is a norm that varies throughout regions and also history and these are reflected in the MCs of the games. As the years progress the general age in all regions has gotten slightly older as well. Kalos is the oldest at around 16 because so much pressure is put on appearances and etiquette that parents are more wary about having their unaware children embarrass themselves. Alola is 11, obviously, this was stated in canon, and Alola is laidback and accommodating in general, since it's a big tourist trap. Johto's is also around 11 because of its strong ties to tradition. Kanto's has been upped to around 13 by the time of gen 7, but was also 11 when gen 1 came out. Hoenn's and Sinnoh's is 13 and the biggest worry is the terrain in those regions; Hoenn is just generally tough to travel and very hot, whereas Mt. Coronet makes parents worry in Sinnoh. Unova's is very flexible since it's kind of a melting pot, though the average is pinned around 14.
School does exist in the pokemon world, but time is blocked off for children to go on journeys and is all together much more flexible than school in our world. If a child decides to finish school first, most regions would finish off high school by age 15 or 16, but most kids do graduate around age 17 or 18 because of the time they spend going on an adventure with their pokemon. Children can also opt to study while out adventuring and be tested out.