Should I give up on her?

I HATE my sister. I can't stand her. All she does is cry, yells, screams, eats, causes huge messes and abandons them, and starts fights with me and my brother, a lot more with me though. Not to mention she is 12 and still sleeps with my mom. About 80% of the things she does aren't directed at me, but the fact that she does them and gets away with them makes me hate her. I tell my parents all the time they're the reason I hate her. I don't think I've had a sincere conversation with her since she was like 6. To sum this up, I'm the outcast, and she is the princess (eww). I go over to my friends house and see his relationship with his sister (a great one, she would do anything for him) and I get jelous that they can have that relationship. Over the past year, I have explained to my mom a couple times that me and my sister should be more "siblingly". Maybe for a day she will be nice to me, but then the next she will be back to her old ways. Just tonight we went out to dinner and she tried talking to me about something and I just couldn't even look at her or respond because I feel so on edge with her. There is no point talking to her because I know like 2 hours later at home she will do something that will ruin a good night. I don't even acknowlege her existance; at the begining of the school year I made new friends and I didn't even tell them I had a sister I just said it was me and my brother. That is something a brother should never do, but I have no option. At this point dropping her from my life is like the greatest thing known to man.