My GF is dragging me to church w/ her family?

[Dante]

So I've been dating this girl for about two months, and I met her family, and they invited, no, they INSISTED I come to church with them next Sunday.

My family goes to church, and I used to go when I was little, until I started to think for myself and stopped going.

This girl doesn't even act Christian, we have sex, go to parties, and we've never talked about her religion ever.

I decided I'll go for sure, to make her happy, but I'm not religious at all, and don't know what the hell I'm supposed to do there. lol

I think i'm just going to sit down, shut up, and wait for it to be over.

Anyone been in a situation like this? What did you do?

I don't want to be rude, lol.