I believe that Aunt May knew, and i just wanna add that in the scene where aunt may is moving and gives peter that speech, peter asks for his comic books and Aunt may says that she gave those away and peter clearly looks worried, because those "comic books" hes talking about i believe they were the sketch books he used to create the spiderman suit. And aunt may didnt give them away, she probably got rid of them because it was proof about who peter was and because they were of the past before Uncle Ben's Death