I'm in a bit of trouble I think

I've been with my gf now for 3 years. We get on really well, the only "problem" I have is that her parents are quite religious. So for the last 3 years I've been lying to them. When we first met they asked me what religion I am and I said Christian, even though I'm actually an atheist. Now I know I shouldn't have lied but I could just tell in the way they asked me that they wanted that answer. <br><br>Anyways I got an email from them a few days ago. They said they'd like to start attending church and that they wanted me to come with them. To make it worse my gf is really close with them so they all go to church together. They'll know I didn't go in a heartbeat so I'm screwed either way. I can just feel it. I can't imagine how pissed off they'll be if I tell them I'm actually an atheist. That's a slap in the face to religious people.