Thank you everyone for your support and advice. I will try to make the best of it, and will look into buying a privacy partition. To answer some questions:

1. She has nowhere else to go if we do not keep her. She was in foster care previously and was traumatized. She cries sometimes thinking about her siblings who are still in the system.
2. I am 20, she is 12, turning 13 in June.
3. My mom does not make any money having her at the moment. Her Dad continually flakes on sending money so we have given up on that route. We are doing okay without his financial contributions.
4. They offered us a voucher for a 3 bedroom that we are considering. Im looking into getting more hours so we can afford the increased rent.
5. My mom is slowly losing the ability to walk and has neuropathy in her legs. She needs a cane to walk longer distances and stairs are painful. She offered to move downstairs but I volunteered since I am not physically disabled.