Do I get over this guy, or ignore the weirdness and ask him out?

Oh sweetheart, I won't make fun of you. I was in the same situation just two months ago! My god it was terrible. I wouldn't advise you asking him out. I personally don't believe it wouldn't work out because of your grade difference. He'll be made fun of by his friends & he might not be able to stand it & you'll just result in getting your heart broken. Stay friends.