I'm 44 years old and still have nightmares about school.
Discussion
I never had nightmares about school, also stopped having nightmares in general at about age 11 when I began to pull up the Minecraft quit screen if it got close to being bad lol
Shortly after I realized I could shoot people and if I did it right my aim would be good and they would also stay dead
My brain stopped trying to give me nightmares, worst I got was about a month into dating my girlfriend when I dreamt I got into a bad wreck with her in the passenger seat, got knocked out, woke up (in the dream) and she was gone