How can explain to my fathers girlfriend that I'm not her child?

I am almost 23, and my father is back in the dating world. But the lady he is seeing is trying to control everything I do. She doesn’t live with us, yet she is trying to have my father give me a curfew. I’m not a child and my father knows that. But this lady has never had children. She also thinks my father will propose to her, but he is not sure yet. But the main problem is, she is trying to have me call her ” mom” instead of her name. I don’t like it, and I don’t want to hurt her feelings, but like I said before, I’m not her child, I’m my fathers daughter.
I have tried to tell him what is going on, but I know he is lonely, and I don’t want ruin his companionship.
Please, help me. I don’t know what to do.