Australia doesn't have a "prom" but rather a "formal". I didn't have a date either, so I decided to just take the piss out of the night. I don't remember my exact outfit except for the three bow-ties. I spent most of the night buying rounds of drinks for friends and sitting in with the smokers. I dunno how it is in America, but you're not expected to "dance" and there's going to be plenty of people who aren't giving a stuff (we had our own loud music outside and we were singing the night away until the after party).
Just go and make what fun you can.
