I'm having a slight problem at my christian school.?

Are you sure they'll kick you out? Plenty of us at my Catholic high school weren't Catholic (Jewish, agnostic, atheist, Wiccan) and they didn't care as long as we put in some effort in the religion cles. And if they do care, well, you've already been lying to them, so what's another lie? It's not like you think you're going to hell over it, after all.