If one wanted to write an adult wizard school book, that might be one way to do it. After all, it’s not like everyone leaves school at 18 or 21 in our world.
Though personally, I favor learning magic through an apprenticeship system anyway
Thought of the day: there are so many books about wizard schools, but they seem to mostly be about elementary/middle/high schools. Where are the wizard school grad students? The post-docs? The teaching assistants and the half-time admin assistants working their way through school?