Trad class

Hey all, I have a trad class scheduled for this weekend with East Outdoors (a shop by DC). I’ve gotten trad climbing “instruction” from some buddies and led some easy routes, but I wanted something “official.” Have any of you been in this situation and, if so, what questions/preparation do you wish you had before taking the class? I’m short, I’m hoping to avoid learning bad things from my friends but I don’t know what constitutes “bad.”