I'm choosing Notre Dame over USC but I'm afraid that I'll regret it

From an academic perspective there is no bad choice here. Both are very good universities. If I were a hiring manager with a resume from each school, then I would treat both pretty much equally and look for other ways to decide.

How do the finances compare from each school? Would one require larger loans, or would one put more financial stress on your parents? I don’t think that either is worth significantly more money compared to the other.

If the cost is the same, then you can start looking at other issues. Do both have good programs in your likely major? Which is closer to home? If you go to university and live on campus and are only located 5 miles from home, it will still feel like an entirely different world compared to living at home.

“help me fall in love with Notre Dame and hate USC.”

They are both very good schools. I don’t see how any of us can badmouth either of them in general. What is best for you is something that we can’t say without more information.