A/G can't give orders. Personally, I'd ask for "airfield information" as opposed to "joining instructions". If there's no response you can land as your discretion; just keep a good eye out.
Don't worry about it too much, everyone makes mistakes sooner or later. I'm sure most on here have done far worse, whether they care to admit it or not. Try flying a base turn the wrong way in solid IMC; air traffic love it when you do that. Not. What's worse is that a fellow forum member had only a week earlier told me how he'd done the exact same thing. You live and learn. Hopefully.