I never went to a school dance...yes, even prom night I missed. It's because I had severe social anxiety. So I never danced with a girl. When my kids go to prom, what am I supposed to say when they ask how my prom was? Sigh...fml!
Just tell them the truth. I never went to any of our dances either. I didn't go because I never cared to learn how to dance. Just wasn't interested. My son didn't want to either as it turned out, and for the same reason.
If you kids want to go, let them. But have rules, so they don't stay out too late, don't come home stoned, drunk or pregnant.
Don't worry, I'm sure your future kids won't mind much about their parents telling them their experience with dating, dancing, and things about prom night. Your future kids might even be too embarrassed to want to talk about it, just like most kids are. You should just do your best to comfort them, like telling them not to worry. After all, it's just a dance night. People take it so seriously, though. I mean, even if someone doesn't have a date, its not the end of the world, is it? It's a pretty fun night to just hang out in prom night, too. Especially if you got some friends that also don't have dates. If you do have a date, it's also really awesome. So, basically, I would tell them that they should just relax and enjoy it, after all, how many times does prom night happen?
By the time you have kids, I assume that the work you are doing now to deal with the paralyzing social anxiety will have had some effect.
If you aren't doing anything to learn to deal with it, then I would also assume you won't have any "future kids", because you will need to interact with someone to have them.