Am I wrong for asking to be paid to babysit my own siblings?

I'm 22 and I have two younger sisters, 13 and 10. I didn't grow up with them. I was kicked out of the house when I was 8 for telling my mom that my stepdad molested me and she chose him over me.

I moved in with my "uncle" and my mom eventually signed her rights away and my "uncle" adopted me so he's my dad now. Me and my mom have had an on-and-off relationship and I have hardly a relationship with my sisters.

They are my stepdad's biological daughters and my sisters never have anything good to say about me. They have told me that I'm mentally ill and have told me that I lie about rape. I know everyone is gonna say that they are just kids and it's probably my mom and stepdad putting these thoughts into their heads. Be that as it may, I don't have to subject myself to abuse. Even from my kid siblings. So I don't have much of a relationship with that family.

My mom reached out to me because my stepdad's mother was in the hospital and asked if I could watch my sisters. I said no. One my apartment is too small. And two they won't listen to me. It would just be me being terrorized inside my own home. And I know my mom won't give them any consequences for disobeying me and terrorizing me.

She begged and I said "Fine. For $15 an hour." She asked why and I said for the bad behavior they're going to have. For the hurtful things, they're gonna say to me. For this being last minute. Etc etc. She asked how could I charge to watch the family.

And I said, "None of you have been family to me since I was a small child." She called me a selfish bitch and. Said this is why the whole family hates me. I don't think I was wrong. We don't have a sisterly relationship and they sure don't treat me like a sister. They're poorly behaved and awful. I should be paid for my suffering.