Ending up in the wrong classroom is traditionally read as feeling out of place, on a path that is not yours. It often appears when you sense you are following the wrong timetable in life.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.