And yes, I did the exact same thing
I'd suggest possibly accepting DADA for Defence Against the Dark Arts, as it's an acronym that is used occasionally. And it might also have been fun to include the teachers of said subject.
Maybe add categories for DADA Teachers, Gilderoy Lockhart's Books, The Marauders (by nicknames or by real name), Sorcerer's Stone Defenses, Schools of Magic, Triwizard Tournament Competitors, and Basilisk Victims!
Why don't you try out my quiz
Just type in harry potter basics
Care of Magical Animals
I obviously knew what these courses were.
Or has it simply been too long since I've read the books?