Math is my jam.
I had fun in calc 1/2 and multi-v and diff eq are fun for applications to physics, but the apex (for me anyway) is linear algebra.
One thing I'd suggest is to get into working with a computer algebra system early and really know it well. All the higher maths you'll be taking will use it. I LOVE mathematica but most people find Maple much easier to start with and plenty of schools use matlab. Find out what the school you're going to be going to uses and work with that.