Did I do the right thing? Is my friend jealous of my relationship?

There is a Halloween party on Wednesday hosted by my friend. However, she was rude to my boyfriend last night. And, he told me this. That she was rude to him. She kept staring at us throughout the night. And, acting really unfriendly towards us. He wanted to invite his roomate to the party on Wednesday hosted by her. And, she said no because too many people are coming. She is just acting rudely. Is she jealous of my relationship with my boyfriend? So, I left amessage on her machine that we were not going to the party.