I can't take my roommate UPDATED

My roommate is 18 and a freshman, there are for of us. She is from what she calls "the Beverly hills of Illinois" and is extremely rude. Before we met, as she was the only one the three of us didn't know, she repeatedly texted us not to smoke or drink at all cause hates it, even though we told her constantly none of us do that. The worse thing is she constantly insults her mom. She threw a fit, yes, like a 5 year old, about how her mom signed her younger sister up to see penguins and not her, crying "it's not fair! I wanted to!" In the winy child voice. She told her mother she was embarrassed to be seen with her because she is so obese, her mom is about a size 18, maybe a bit bigger. She also told her mom to "shit the guck up" because her mom told her to make sure to work hard or something. She acts like a spoiled 10 year old and I know I'm gonna snap one day at her

UPDATE

She threw a big enough fit that her mom is letting her go with her sister, apparently it's a trip to California.