Congrats on getting a choice like this.
This is a no-lose situation, of course.
An admissions officer told me that 70% of students change their majors. Most people your age don't really know what they want to do. Few wind up doing for a living what they thought they'd do when they got in.
3 of my 7 roommates are or were in investment banking at very successful levels (partners at Goldman, when they were private, etc ). Majors were psych, chemical engineering and politics.
Virtually all investment bankers above the peasant level have MBA's - I've been talking to a number of them in the past few weeks. One majored in religion.
My prejudice is to pick the school that fits you. Princeton and Penn both have stellar academics, but the schools are quite different. One is in a richy suburban college town and one is in a big city.
If you haven't spent overnights at both of them, I'd recommend doing that and then make your decision.