I'm not going to ask my best friend to prom even though she wanted me to
Did something happen to you and your friend?
Because, she doesn't like boys and I don't like girls.
I think once you explain your reasoning to your friend, she will understand. It doesn't mean you have to like the other person to attend prom. You can go as friends and have a good time.
You're right, I'm going to ask her right now.
Plan the night ahead and she will remember it for the rest of her life.