just-shower-thoughts:

Students at Hogwarts must have struggled a lot when they got older because the literally stopped learning math, grammar, social studies and other useful subjects at age 11.

No, I’m sure they were fine. I’m approaching 30 and I can tell you that I haven’t used most of the stuff I was taught in school past middle school because it’s irrelevant to my life. Even when I was a certified pharmacy technician for several years, I still only used middle school level math. I don’t feel like high school benefitted me at all. I never use anything I was taught in those years. They don’t teach you valuable life skills that you need as an adult. The US school curriculum is a joke to me. Teach kids how to write resumes, do their own taxes, apply for car loans, cook on a budget (and cook in general), and other useful things. I graduated from high school over a decade ago and I have used geometry 0 times. I’ve never needed to recall facts about The Crucible. I’ve never needed to do beta and alpha decay equations. My career choices have never and will never use most of what I learned past middle school.

TL;DR: US schools don’t teach anything useful after middle school so I’m sure the Hogwarts kids were fine.