AITA for being nice to my older mean sister, even though she’s always rude to me?

So, I (13M) have an older sister who’s really mean to me. She constantly bosses me around, insults me, and doesn’t seem to care about my feelings. Despite this, I still try to be nice to her. I’ll help her with things, try to talk to her, and I don’t always respond to her meanness. I keep hoping that maybe if I’m nice enough, she’ll treat me better.

But honestly, it just feels like she takes advantage of my kindness. She’s always rude, gets mad at me for no reason, and doesn’t respect me. It feels like I’m the only one trying to keep things peaceful, while she just does whatever she wants without caring about me at all.

My other siblings have told me that I shouldn’t let her treat me this way, but I still try to be nice to her because I don’t want things to get worse. It feels like I’m constantly walking on eggshells around her. I know I should stand up for myself, but I keep thinking that if I’m patient, maybe things will get better. But so far, it hasn’t worked.

Am I the a-hole for still being nice to my older sister, even though she’s always rude to me? Should I stop trying to be kind, or is it okay for me to keep doing it, even if she doesn’t appreciate it?