My Sister's Such a Freaking Bytch??

My sister is getting really annoying..we share rooms and she keeps it dirty as heck!!! Ill tell her "please clean the room, its really dirty.." And she'll be like "Stop damanding people,calm down ill clean it later.." she never doees..shell go straight outside and play with her friends instead..i told my mom but she doesnt doo nothing..my sisters younger than me...as well..one day i told her how dirty she was and threw away all of her things on the floor away..she cried and was like."stop demanding people!!!! i swear i clean better when no one tells me to clean, i swear i wanna diee i wanna run away!!!!" she was screaming supeerr duper loud..so i was like stfuu!! so for a week i didnt bother. i was getting even madder becuase the room was dirtier, and she said if i didnt bother shed clean..so i got so pissed i threw all her tthings at her soo hard,,,she just sat and cried and said she wanted to die.. and run away again... not only is it the room prroblem but it's everyday things..i askd what the time was and she was like "idk i really dont care check urselff." she rolled her eyes at me and i wasn't even mean...orr when i said "why did you break the scissor?" she was like ignorringg me,and said "nun of ur buissness." im really getting mad to the point where i wanna punch her in her face... she has a attitude on everything, and she alwas thinks shes right...she told me "i dont like your personality so change itt when your talking to me.." im really pissed, cuz shes such a bytch..shes 11 or 12 and very...what shud i do,?? i've tried talking to her but she puts her fingeers in her ears and ggoes "lalalalala" I NEED HELP NOWW PLEASE!!!