I'm not a lawyer, but I can provide some general information. If you're in an abusive situation, your safety is the most important thing. If you want to live with your mom instead of your great-aunt, it might be possible, but there are legal procedures that need to be followed.
You can talk to a trusted adult, like a teacher or school counselor, about your situation. They may be able to help you figure out the best steps to take and can also help you contact appropriate authorities if necessary. Your mom may also need to seek legal assistance to change guardianship, which could involve going to court to prove that it's in your best interest.
If you're in immediate danger or feeling unsafe, please reach out to local authorities or a crisis line in your area for support. Your safety and well-being are the top priority.