High School:
High school courses can't in any way prepare you for college courses. You will do yourself a big favor to become disciplined, and figure out what your study method is (I can give you pointers on that). Also, take up a minor/double major in an unrelated field. That will make you... "different".

And no one should give you a straight answer on what YOU should major in. that's silly just like those stupid test which tells people what career they should pursue. what a joke!.
Advice on "fall back plan(s)":
Here's my story, hopefully you can see the "big picture". I came to college with the intention of becoming a doctor. Now, broadly, my mind is made up that even if "becoming a doctor" takes an unlikely turn, I still want a career in medicine/hospital field so my ideas of "back up plans" were to look into other careers in medicine. So my plan is basically put myself in a position where I have options later on. Meaning, if this doesn't work out I could always go into this, or that or that. If all else fails, I can use my degree in my major to enter medical researching etc.
Simple and short:
Make up your mind on a BROAD field that you are interested in and put yourself in a position where you will have options later on. Take up a minor if possible you could always declare that minor as a major.