What would Carrie have majored in when she went to college? Where did she go and how did Saul find her?

I can never remember if this is canon or not but I always just assume Princeton.

We don’t know the answers to the other questions but we can speculate. I’d guess her major was Political Science or Foreign Relations (I think I read Arabic Studies once too). I’d assume the CIA has active recruitment operations at a bunch of universities in the US and I’m guessing that’s how Saul found her.