My sister is selfish and immature. Is it bad if I don't want anything to do with her?

To make a long story short, my sister only cares about herself and she is rude. Everything she does pisses me off I can't stand being around her. She's 21 and I'm 20...I go to college away from home and she just moved back home because she was failing and all she did was party. She's irrespsonsible and lazy and the only time she does anything if she benefits from it. She always pulls the pitiful "my life is worse/harder than yours" card on me just because I actually try I'm school and it pays off with the good grades I make. She is jealous of me and always makes me feel guilty by saying "who do you think you are, you think you're so perfect". My question is- would it be wrong (I guess morally) if I just had nothing to do with her from now on? She never grows up.