Teachers should graduate backwards
In teaching school, students should start TAing, eventually teaching freshmen in their final years.
When they graduate, they should be placed with 12th graders, and graduate to 11th grade for the next year, and so on.
Kids are easier to teach when they’re older, since they’ve been in school so long already. The younger a kid is, the less they already know, both in subject matter and scholastic habits.
Teaching the youngest kids is tricky and a serious responsibility, which should be entrusted to those who have subtracted bits of that knowledge one by one, and faced the associated challenges.