New Undergrad at Northwestern - Looking for Guidance

I'm feeling a little lost and purposeless going into my first year as a college student. I just graduated highschool and I've signed up to pay out the ass to go to this brand name University, but I don't have a concrete idea of where I want to end up after (although I know I'll have some debt to carry around no matter what).

My current plan is to major in Economics and either Mathematics or Statistics, or go through the MMSS program. I think I'd also like to pick up the certificate from Kellogg in Financial Economics.

I'm a little confused about how this whole timeline should look - at what point do I hone in on a finance-specific role I'd like to fill when I come out of undergraduate studies?

My understanding is that it's best to intern between sophomore/junior year as well as junior/senior year - but how am I supposed to discover what sort of work I'd like to be doing? It seems like there's a LOT of different careers I could make for myself, either in finance/banking or even consulting.

Can someone provide me some sort of resources to help me narrow down what sort of job I'd like to have after I graduate? Or at least give me exposure to the opportunities that would be available to me after I graduate?

Any general advice about college, living on my own, making connections, even life at large would be greatly appreciated.

Thanks for your time guys.