AITAH for blocking my 14 year old half sister on TikTok?

My (24m) half sister (14f) has been on TikTok for like a year now and she's been using it for months to annoy me. Sometime in August or September she shared a TikTok from someone we don't know about how they met their stepmom and started out with you're not my mom and ended with saying ILY mom about the stepparent. My half sister told me to see how things are meant to go and this is how you should be with my mom now. I told her it wasn't that way for everyone and she should understand that. I even said she should send it to her BFF and see what her response was and told me to shut up back.

Once that little talk happened she started searching for all those posts with that trend for stepparents and she flooded my DMs with those. It was constant and she sent repeats a lot because she couldn't find all the ones about stepparents who get called mom or dad by the end. I didn't reply and after a while I stopped opening the DMs with her completely because she was getting on my nerves and every time I saw her she was trying to bring it up. We had an in person talk and I told her she shouldn't be trying to bug me about that and I told her to stay out of my relationship with her mother. She corrected me and said our mother and I told her we didn't have the same mother and if she didn't back off I'd block her on TikTok and speak to her less.

She didn't back off and I delayed doing anything but last month she went absolutely nuts with the DMs and shared 12 of those TikTok's a day. Most of them were again repeats but the point was she wanted me to watch them and feel bad. She got worse last month because I made a TikTok about my mom and it bothered her so much. So I blocked her TikTok and now she can't send me any. I made my account private too so she can't see shit.

She cried to some family members about it. Dad was the first one to ask me to please just talk to her and figure it out. I told him I had tried and she just got worse. He asked me if I couldn't just not let it get to me so I don't hurt her feelings. I said no. Then some extended relatives spoke up and told me I'm an adult and the older of the two and should be able to handle it better. I don't see what else I could do though. She won't stop and nobody else will step in and tell her she's wrong.

AITAH?

Also for some quick background on why she's doing this. My mom died when I was 6. My parents marriage had been over in everything but name for a while so dad fell in love again fast and married my stepmother. I'm not close with her and never saw her as a second mom or a bonus mom figure. Sometimes it bothers her and other times it doesn't. But my half sister knows that it bothers her mom sometimes and she never understood my position and she's just too unwilling to consider it from my POV. Things are okay with my stepmother but in my eyes she's just my dad's wife and half sister's mom and our relationship isn't really anything beyond civil.