Wow what a predicament ES sorry you have to face this. Good luck with what ever you choose to do.
This is a very unfair situation she has put you in. When I was 15 my parents made me choose between a roof over my head and the cult, I had to leave. It was hard but I stuck to my guns, no one was forcing their religion on me. In your situation it may be easier to pretend to concede a little, your livelihood is at stake.