If medicine is your goal and you can maintain a high GPA with math then go for it IMO. Wait...you are a sophomore in highschool then? Well thats pretty good way to go, try to do as well as you can. If you do decide to be a math major, just take the credits for Calc BC, that way you can start at calc 3 at the very least if they dont transfer your multivar, diff. eq., and linear algebra....what will most likely end up happening is this: Credit to waive Calc 1 & 2....you start at calc 3 aka multivariate, and the ones you took at the Junior College will count toward Elective credit...which is not bad...because say you get a total of 12+ credits...and you take calc 3 get A in everything else...your GPA will be very high because those 12 credits will take on the GPA you get your first semester of college, making it harder for your GPA to fall.
Dont do online...im sure you can self study physics C and since you did well on B, you should just put in a bit more effort to look for another 4. Just ask your college office first if they can order the test for you when the time comes (they should) and then you will be cleared to take the test.