House of 3 women

I’m in my mid 20’s and live with my mom and 16 year old sister. I stayed at home to help my mom out with my sister since she is a single parent and is always working. Around Christmas my sister just completely changed and started being really secretive. As soon as she turned 16 a few months later Mama let her get her license and got her a car. She then dumped her boyfriend that we liked and started going out with a new guy that is kinda questionable. She stopped hanging out with her usual friends and started hanging out with a new group. She is never home anymore and keeps breaking her curfew. She won’t talk to anyone in the family except one family member who gave her a key to their house. She keeps showing up unannounced with her friends to their house even when they aren’t home. The last time the family member was at work and had plans with me to talk about something private that was going on with me and my bf. When my sister found out she showed up at my work and started fussing at me while I was dealing with a customer. My mom has done nothing except tell her that she couldn’t spend the night at one of her friends’. I want to move out before someone does something that gets someone in trouble and drags me into it. My mom wants me to stay quiet about what my sister is putting her through but other family members and my boyfriend can see and keep telling me to get out of there. My only problem is I can’t afford to.

Update: my sister has maxed out two gas cards 💳 now. Mama confronted her about it since we now have no useable gas cards and she just spent the night at a friends to save gas.