Can someone give me some helpful advice ?

I REALLY hate my sister. She is evil, nasty, and disrespectful. At school, she is the best, kindest person ever, but her friends don't realize her true bad nature. She's also too naive to notice. She is so annoying, cruel and disrespectful to ALL of our family members and is too blind to acknowledge that. It isn't fair how she treats people at school better than her OWN FAMILY. I can't help this evil feelings, but she says the cruelest words to me and I'm older than her. The b***h treats me like a stupid idiot and im OLDER and SMARTER than her. Sometimes she treats me like an acquaintance, and then she calls me *****, ho, stupid idiot and more. It is from her where I developed my growing distance from my family and want to escape in my imagination. I feel EXTREMELY GUILTY saying this, but sometimes I think of killing her because I now HATE HER SOOOOO MUCH. She doesn't even let me tutor her because she says I teach TERRIBLY, but she never really listened as many cosider me an efficient tutor. Today, I was close to attempting to choke her (we're only 2 years apart so I probably wouldn't get far) but she pushed my arm away. I've been controlling my temper for SO LOOONG. I dunno where my limit will reach because I'm somewhat stronger than her. She's close to pushing me over the edge. She insults NONSTOP, and always has this cruel or malicious look in her face.... I wan't to wipe it of.. FOREVER. Don't worry, I won't kill her because of the future ahead of me, and also because i might still have a tiny ounce of care and tolerance for her.. but right now I just can't find it and feel like killing her. Another thing that wracks me with guilt is that I wish my best friend jessica were my sister. When I see my sister sleep she seems innocent, but it only reminds me of bad thoughts and memories of her sometimes... I'm sooo confused. I don't need a reply. I just had to write this to get rid of this negative feeling... I THINK IT's WORKING. I see that im also at fault for not being so patient. When the cruel feeling returns, I'll see if this alternative helps me stay calm (in paper, not the internet)