Jothar, in my experience, most of the students who go off the derech in college are kids who are waiting to be out of Yeshiva and their parents house to do so. (yes, this is just my limited experience) I could have told you who from my high school class wasn’t going to be frum anymore well before they graduated.
I went to Stern for a year but it really wasnt the school for me. I wanted a much more technical school. I was choosing between Virginia Tech (no Jews), University of Maryland (tons of Jews) and Brooklyn Polytech (few frum Jews, but not much of a dorm life / campus life). Virginia Tech was my first choice for education, but my family was strongly against it. We struck a bargain and I stayed in NY for school. Luckily for me, I met my husband there 🙂
Interestingly, the engineering school was mainly male. I was the only female student in many of my classes.