Is it normal that i'm willing to do this even though i am an athiest?

Yes. She also wants to convert you

I can't go into a church, I'm afraid I'll burst into flames. Holy water burns me

Yes, you were being polite.

Tell them to get you a sandwich and a blowjob and you will start believing.....

I think it is a good experience and churches should be welcome to you. A youth group is for young people to get together and not only get closer to God bu closer to each other. You might make new friends and want to go again. I am an atheist too. But. it would be a good idea not to say anything about your beliefs until you build a trust or you can be an ass and debate their beliefs because you will probably not go again.
I used to go to Youth Group but the people there were whiny and always had some kind of 'drama' so I was bored with sad people. I didn't get closer to anything but a wall.

Religion effd me up

Totally normal, I don't belive either but my best friend is Mormon and go to her youth group and even go to church sometimes! And I still haven't converted ;p

No, don't go or you'll burst into flames.

the things people do for poon. the stuff really is addictive

Once me and a friend got invited to a youth group. We're both atheist but I stayed back. After it she was really sad. She said that things went fine until the end when they had a group prayer. No one said it to her face but her pastor pretty much said "I'm so glad we're Christians. Non believers are evil."

No one likes being called evil. You're normal for accepting but don't be surprised if things get uncomfortable. Just leave if they do.