So this just happened a few hours ago

I need help with a situation in my house

Some background: I am in 14 in 8th grade, I have a younger sister who is 10 in 4th grade. I occasionally make self-deprecating jokes (not around my parents) around her, about my weight, bad looks, stupidity, etc. Sometimes I try to act more her age around her, less mature. She'll also tell me "I'm not the boss of her, I need to stop treating her like I'm her parent" when I'm just trying to help. (example: "No, I don't think we should go to the park. There's confirmed cases of coronavirus all over the world. I don't want you to get sick, even if you have an immune system you can still get hurt and I don't want that.")

Today I asked her to play a multiplayer game with me, which she used to like, I didn't know she didn't like it anymore. She said to me, "The more you nag me to do something, the less I will do it."

BS. If I ask about something one week and she says no, then ask the next week she'll pull this bs about me "nagging her" when she's much worse than me. She'll bother our parents endlessly about one single thing, then ask 10 minutes later as if it's been ages since she last asked. (example: "Daaaad, why can't we go to the park? I won't get sick! I promise! Please!! Ugh! You guys never let us go anywhere!!")

Whatever. Fine, I don't need her to have fun. I'll do something on my own then. I go back to my computer (I also had ~40 minutes before I had to go to bed) and my sister walks over and wastes almost 10 MINUTES telling me "oh you're not ugly or fat. You're beautiful and smart!" (bs but ok.) She doesn't let me speak during this whole ten minutes, during which she's grabbing my wrists, rubbing her hands on my face and pulling my hair for effect. I tell her to stop and I pull away from her. (Remember, she's 10 years old and I'm 14 years old..) Then she says "I wish you'd start acting your age a little more."

Oh really?! You want me to change from submissive, quiet girl acting your age to your impression of all teens, an "angsty, angry mean person"?! Fine. I'll give her what she seems to want. I say a little louder "I said stop touching me."

B*tch slaps me across the face. WHAT THE F*CK?! I ask for her to listen to me, it is definitely not ok for her to do things like that.

I ask for her to stand in front of me and listen, like I was, for a couple minutes while I talk uninterrupted. Well, I guess that's too much to f*cking ask from this b*tch. She keeps walking, hardly listening, as I explain that you don't slap people when they tell you to stop touching them! Interrupts, leaves me alone, doesn't give a sh*t about what I have to say when I let her rant and lie to me about how I'm "not stupid or ugly" (yeah right, f*cking b*tch.) I know I am those things, and guess what? I don't need her lying to my face. Calling myself those things is almost motivating me to change.

I proceed to spend the rest of the free time sobbing alone in my room, little assh*le is unfazed and goes back to watching YouTube downstairs.

I don't know if other kids are like her. When I was 10, I guarantee, 1000%, that I was never, ever like this. Not in my life.

TL;DR: Sister 4 years younger than me wastes my time, tells me to be more grown-up, then slaps me across the face when I tell her to stop touching my face and grabbing my wrists (keep in mind, coronavirus has been confirmed in our county.) She doesn't give a f*ck about me when I ask her to stop and I cry myself to sleep.

Sorry for the long post