I hate my sister please help!?

She's so annoying and makes me either end up crying, screaming or feeling plain alone and misunderstood. She's 19 and I'm 13. She's autistic, but I swear she's evil. Whenever I step just a teeny bit out of line she yells "Mom, mom! Dad, Dad! She's teasing me!" They come over of course and I'm sent to my room. "Why do you have to tease Molly?" Mom asks me. I say, "She's the one that's got it easy. She throws me around like a doll (which is true, she attacked me with a chair, bopped me on the head so hard it made me dizzy) and do I tell on her? NO!" For instance, today's the big game between the bears and the packers, right? My dad's friend comes over to watch it (also my dentist). They go downstairs. Molly comes into the family room, perfect as always."Do you have any earphones, Molly?" I asked. "No!" She yelled. I wanted to whisper "Shut up!" (I didn't) I just said, "Be quiet." It was like I set off a bomb. "MOM! MOM SHE'S TEASING ME!" My mom covered her mouth and Molly pushed her off. "Can't you stop teasing her? Just stop." Mom said. I say, "I just told her to be quiet." Molly screamed, "You be quiet! MOM!" I started crying, "Just forget it! Forget it all!" Why does she have to be so annoying and evil? Why can't she just learn to shut up once in a while? I need advice, because she keeps ruining my life.