My sister is turning into a bitttch. Lol why ?!?

[MaddakinzBeyotchez]

I'm 15 years old and my sister is only 8, her name is Sierra and she is turning into a bossy brat.
I have a kitten and its only 7 months old and we got it when it was 4 months old and its name is Sneakers, but a few days ago my sister said "I'm naming her Pookie and if you have a problem with it then I don't care" Like.. ? Really? She's been stealing stuff out of my room and I have a BIG family so I share a room with my older sister, Kayden, she's 18... But Sierra wont steal her stuff, only mine! I'm getting tired of her. She's bossy, and since she's my little sister my mom said to not argue with her. She's been hitting and a lot of other stuff! Yesterday my boyfriend came over and she hit him in the nose and make him bleed? FOR NO REASON, and when he left I asked why she did that and she said that I deserved it? I NEVER DID ANYTHING TO HER. Please help before I knock her head off her shoulders. c:

 

[melanie]

She just wants more attention from you.you guys prob used to play together or something. She prob just misses you.dedicated her some girl time go to the movies shopping but just you guys. She's really crying out for you.