if you really don't want it to lower your AAoA, you can try to ask them to delete the account entirely and not report it. it can be done, if they're willing to. however, like others said, you have already taken the inquiry hit. they can remove the inquiry as well, if they want to, but chances are they will not. Only lender that I have seen that is willing to remove the account and inquiry entirely is Chase (I didn't go ahead with it though so i can't tell if it's for real or the CSR/manager is bsing me).
My best advice is to just keep the card 