Interesting question.
To be honest, I’m split.
You would think I would support mandatory schooling up until age 21. But how many years really are necessary to learn the basics that makes for a literate citizenry?
5th, 6th grade?
How much do we learn in high school do we really use in real life? What I remember back in high school, it was like a forced buffet. You had to have a taste of everything. Although it was in those years that my writing skills grew.
There is much more that is learned in school than simply the subject matter of the classes. Kids learn how to learn, they develop discipline to stick to a schedule, challenge themselves with subjects that they don’t necessarily like or want to learn about, they learn social skills, sports and extra curricular activities etc. It is the best environment to prepare them for the real world on many levels.
It can definitely be improved in many areas but it is a great system and essential to a prosperous society