Two-faced sister

I don't get my sister sometimes, one minutes she's annoying as hell, the next she's being a straight up bitch, I tell her I'm sorry about something and she's like "Sorry's for assholes" I'm trying my hardest not to kick her ass cause I don't want to get in trouble but she keeps pushing me to do so. *Growl* You know she should've stayed in college like the other smart asses there! I just want her to stop being a pain in my ass and just leave me alone, I get that she's stressed from college but that's just a lame excuse for me, and now she's a big internet star *sarcastic* Oh great not I even less important to the family now that she gets all the attention on youtube and in the house, just because she's getting more attention doesn't mean she has to treat me like dirt, and she's the only person laughing when me, dad, or mom are in a bad mood. We're trying to get her to leave us alone so we can cool down but NO she has to keep pushing and making it worse! That's her major problem; She doesn't know when to stop, she keeps pushing til she gets a reaction.