AITAH for refusing to babysit my sibling’s baby even though they say I “owe” them?

I (20F) have an older sibling who recently had a baby. Ever since the baby was born, they’ve been constantly asking me to babysit, even though I never agreed to it. I work full-time, and when I’m not working, I just want to rest.

It started with them asking me to watch the baby for “just a couple of hours.” I agreed, thinking it was a one-time thing, but that turned into dropping the baby off unannounced and texting me "Hey, I’ll be back soon!" only to disappear for hours.

Last weekend, they called and said they were going on a “date night” and asked me to take the baby. I said no because I had plans. They freaked out, calling me selfish and saying I “owe them” for all the times they helped me when we were younger. They even pulled the "family helps family" card, but honestly, it feels like they’re just using me for free childcare.

Now they’re mad, and even other family members are saying I should “be more supportive.” But I never agreed to be their babysitter, and I feel like they’re taking advantage of me.

AITAH for refusing to babysit?