As everyone else is saying, you'll be okay. I know that my chapter is an anomaly here on GC, but religion was never a big issue. We had a few sisters who were Orthodox Jews, so we didn't have events on Friday nights (and if we did, they were excused).
We actually have a lot of sisters who calmed down after they joined our house. The first semester or first year of college is a time when a lot of girls are wild, and sometimes joining a group that is cohesive as a sorority can show the girls that there is more to life than partying and hooking up. Plus, they're usually so busy during New Member Ed that there's not as much time to be a party girl.
