Stepdaughter help😩

Her dad and I have no idea what to do. She’s basically a teen but from what people have told me...her behavior isn’t normal. She’s told me stuff about her mother before, I’m not sure how true it was and if it was true, there’s never been “proof.” She’s told me that her mother has smacked her before but covered it up with makeup. She’s told me quite a few times she wants to live here but doesn’t want to talk to her mother because of that and she says she gets yelled at and gets told she’s not old enough or mature enough to decide on something like she just wants to give up. We mentioned her wanting to come over more a few months ago to her mother but it went no where. She told me the conversation that happened and she didn’t want to get in trouble for disagreeing with mom.

So, she hasn’t been getting up to her alarm so we gave her an earlier bedtime and she still doesn’t get up to it. This morning I walked into her room to wake her up, she got an attitude and I told her she needed to get up. She crossed her arms and crossed her legs and said, “I’ll get up when you leave!” I told her she needed to get up then I’d leave (wanted to make sure she got up). She stood up and crossed her arms, I put my hands on her arms and told her she needed to calm down and lose the attitude. Then she flung her arms up and shoved me across her room. Then tried to say it was self defense and I tried to choke her.🤷🏻‍♀️🤷🏻‍♀️ I said, no, I had my hands on your arms, you flung your arms then my hands slid up. If I was trying to choke you, you’d know. I’ve never tried to choke anyone in my life. ...we were in the kitchen and I asked why she thought I was trying to choke her and showed her exactly what happened again. I mean, I get it from stuff she’s told me about her mom but why would she think I’d do that? She said, well, I didn’t do anything when mom did that stuff bc I didn’t know what she was going to do. ..... I’m just at a loss and have no clue what to do. Considered bringing it up to her mom but don’t want to find out what would happen and make me feel bad about telling her.