AITA for going no contact with my mom?

i(21 f) am pregnant, my brother(16) has attacked me on multiple occasions, once while pregnant. we don’t have a dad, our mom(41) treats him as the golden child and has since he was born, she doesn’t care when he hurts others and when i lived with them would get mad at me when i’d threaten to call police she said she would tell them i attacked him and got mad when i would record him. my brother freaks out when told no, recently he wanted to go out and when my mom said no he jumped out the second story window(broke four toes) the same week he ran away and was found by police with weed and fentanyl in his system. CPS opened a case obviously and when they asked my mom where he could have gotten the drugs she told them i used to give him weed which isn’t true, now there is a case open against me. i tried to talk to my mom to see why she would say that and she tried to gaslight me about a bunch of non important things and claimed she never said that, then told me she was having a drug test and if i had any tips to pass them.. later she called my grandma and admitted to lying to me about what she said to the case worker. i haven’t spoken to my mom since that conversation two weeks ago.