Prom help!

So I got a close friend (girl) and I was going to ask her to prom. She does not go to my school. idk if she likes me or not but we're close friends. Anyways some guy at her school asked her to prom. Would it be wrong if I asked her to my prom? Is it against the bro code of conduct or something? I need help. If I don't ask her then I need to ask someone else quickly, thanks!!