I (19F) just slapped my younger sister (15F). Aita?

We have a typical sibling bond luke we do bicker but this types of fight happened after literally 7-8 years.

For some backstory, few months ago we had some fights happening typical sibling stuffs nothing serious and then she got mad and slapped me. It was outside my home I'm sure few neighbours saw it. I didn't even know how to react cause I don't remember anyone slapping me. I ding even remember what the fight was about. Anyways, I did feel so bad that time but mom didnot scold her so maybe she thought it was okay. She even bragged that she slapped me and I am very scared of her now.

For back to present, I was tryna joke around with her and she was lying in her bed watching yt shorts. I went to lie down beside her but she got irritated and immediately said no but I didn't get up. She then she slapped me I got mad and I slapped her right back. She got even mad and she got up from her bed and I did too and then she slapped me once again. I pulled her hair but she had her ears pierced a few days ago so it hurt her so she started crying. I immediately felt so so bad about it. I said sorry and left.

Now I'm replaying everything in my head and I did go to talk to her again saying how does she feel and stuffs but she went under the blanket she's mad I get it. I know I'm wrong but she shouldn't have slapped me just cause I didn't say anything the first time. Two wrong doesn't make a right. How can I make this better?? Idk what to do.