Personally I'd "home school" my kids from day 1 (yes, the day they're born) and spend a crap load of time with them before they actually start school.
I'd like to be able to lay a firm solid foundation for them, to get their young minds thinking for themselves. And I will then ask them if they would like to learn more at home or at a "big school"
Social interaction for kids is very important, I can just see how my two nieces are flourishing at school. My sister tells me they're growing up really fast and I'm missing it ....... but to the point, kids need the variety of opinions and different things they experience in social enviroment.
I won't even bother sending them to a private school for "better" education as those people are also prone (if not more so) to peer pressure and weird cults/drugs.
Teaching your kid well enough to think for themselves BEFORE they go to school is paramount. They'll ask the right questions, they'll learn more, they'll be more open to change.
What the OP said about the friend is kind of weird. You're going to get these kids who will get into fights in their ADULT life about Jesus and the "unpure" stuff other people do. All would then end up with an unplanned pregancy with some pastor's son....
seen it happen a million times...