I'm sorry you've gotten attacked for that so much. It's truly sad that people don't see how terrifying it is to be a woman and having to turn down a guy. Especially nowadays. You could be as polite as possible, "oh, thank you for asking, and I truly am flattered. But I was hoping to go to prom with someone else" and you still have a chance of being stabbed to death. Times is hard for us women and it'll take the death of men for people to realize it.