Dating someone who is quite religious, so I'm scared to say I'm an atheist

I told her I've stopped going to church for a few years, but she knows that that doesn't quite mean I've stopped believing. She's all about her faith, but I know she'll go back home if I say I'm an atheist. She's been very kind to me, and we're only a week into dating, not ready to close this chapter of my life yet. What do I do?