Ironic that the OP's username is id10t.
I went to Catholic (My family is Catholic) K-8 school and high school. In high school we had non-Catholics there. One guy was Muslim, a couple Jews. It was no big deal. We went to mass but they did not have to participate, just sit there respectfully. In middle school it was every week. In high school it was like once a month and on holy days.
Now I am at a public university. I can say I am glad for my parent's actions during my formative years. I still hold firm to the values (not so much the religious ones) I was taught. Mostly about hard work and treating people with respect.
BTW, we were taught intelligent design. So it was evolution just with the caveat that God started the ball rolling so to speak. So there was no denying of science's explanations on how it all happened, just why.
Private school kids are still kids, however. The system is not perfect, but from what I hear the environment is much better than public schools.