I hate my sister sometimes
Thats terrible. Why hate your sister?
Because she's always telling me what to do and she's such a busybody
I understand that conflicts can sometimes happen with family members. It's not good to hate your sister though. Pent up anger can be very self destructive.
I'm still getting used to her, she's kind of annoying. She's been coming in my room, telling me to tidy it up. That room is my bedroom, not hers. If she doesn't leave me alone, I might have to do something about it, and it won't be pretty.
You might find her annoying but her telling you to keep your room clean might be a favor for your mom. If you don't clean your room, your mom might have to. Let her know that you'll clean it so she will stop bothering you.