My boyfriend asked me whom I was going to the dance with?

If he's your boyfriend, who else would he take? You should have said, "I'd like to go with you."

I am 18. I also answered your other question.

Weird. Was his tone implying that he was asking in an oblivious way like sarcastically joking around? If not, that's a little weird... if he says he's definitely going even if you don't, then see if he plans to go with you if you do go. If not that's a little bit weird.

I believe you also posted a question about whether or not you were attractive, from what I see on your picture you seem pretty attractive to me. I don't see what his problem would be with going to a dance with a beautiful lady like yourself.

Best of luck to you. If he decides not to go with you, then I'll bet anything you can get a better guy, do so and prove to him you were worth it.