You should go, and make it a point to enjoy yourself. I was planning on going stag to my high school prom, but a really awesome girl ended up asking me to take her instead. I was super psyched and thought it was going to be the greatest night of my life... needless to say, my high expectations were smashed when I caught my date making out with some other guy at the after party. I ended up leaving early and spent the rest of the night sulking by myself.
Honestly that one thing I regret is letting her ruin my night. If I could do it all over again I would make it a point to enjoy the night, no matter what everyone else is doing.
You should definitely go. Have fun. It really is a once in a lifetime opportunity. And don't worry about everyone else, do what makes you happy.