Context: my sister (28F) had a baby last year october and she is a shit mom to say the least ( she does absolutely nothing for the baby and she is extremely incompetent and she chose an even more incompetent man to have a kid with). My mom, dad and i (20F) have been taking care of the baby. I babysat from January to july for 70us a month (i was deprived from school to do this btw) i can do many aita stories with this family

Fast forward to now, my mom's doing renovations on the house and the baby started daycare in September. Last night she told me that she has a lot of stuff to buy the day after( paint, fans, wardrobe etc) and I knew she was hinting at me having to watch the baby ( my mom gets the baby ready for school on a morning and collects her after school). But she never actually got to asking me but i figured it out. This morning she woke me up asking if im still going to watch the baby and I said yes. The baby doesn't like me anymore because she has gotten used to my mom and has serious attachment issues with my mom. So every time i come near the baby when my moms around she would scream and cry and throw a tantrum because she doesn't want me to take her away from my mom. So every single morning the baby follows my mom and cries occasionally so my mom can pick her up. I can usually hear them and the baby crying every day but i dont help because id literally make the situation worse. Now it's suddenl a problem this morning. My mom's taking the ba' school because im not "helping her" when I litera.., dont every morning and she said that im the worst out of my siblings and i am a selfish and bad person. I am extreme confused because I literally woke up at 6am and told her that i would watch the baby. And I do this every morning(not helping with the baby). AITA??

Edit: I saw a bunch of comments suggesting that I move out. I genuinely wish I can but I am not from America and finding a job where I am is difficult. I also only just got a bank account last year and my mom chose to do house renovations and buy a vehicle instead of helping with my education like she promised( because our beliefs don’t align anymore). I also watched the baby for 7 months for 10hrs a day. And i did agree to watch the baby. My mom got frustrated before i got the chance to.