Was I in the right? Please please please reply.?

Last night I spent the night with some of my friends. The girl who's house we were at, she's sort of a brat. She lies all the time to make it look like she didn't do anything wrong. Sometimes I let it slid but last night she was just being horrible! She lied saying her little brother meant to get watter all over the place so we'd all slip and fall even thou he just wanted us to come swimming with him. She also lied when ever we were joking around talking about what'd he'd be like when he grew up, and Bue miss hared us and thought we were making fun of him so he ran away crying. I felt horrible and was trying to make him fill better. But Katie kept saying to just lie and say we were talking about the guy down the street. Then she started ruining the night, like we wanted to play a game and when she had to be it she refused to play. And she got hit in the head with a basketball wail he we swimming and she kept saying she was going deff in that are. Which is a bunch of crap. Well her and everyone else there want me to call my bf and put him on speaker where they could all hear so I did. And almost the whole time we were talking to him she kept whispering side comments to my other friend about my bf being fat. (he is big. But alot of it is mussel. He works out alot and plays football.) Well I told my bf I'd call him back, hung up on him, and said stright into Katie's face that she was fat to. (she's not skinny, ok) Everyone was like staring at me then she just got up and walk away. Now she's saying that I use to say stuff about her when ever she use to date Braxton (who is kinda fat. Not musley). Which I never did :P and she just made up. I fill really bad but this girl gets EVERYTHING SHE WANTS! I'm not going up to her and apologizing until she does. I forgive her for making fun of my bf but idk if she forgives me. Was I right? To call her fat after she made fun of my bf right in front of me?