what's much more important is getting good grades in college (which may mean getting a degree in something besides biology if that's easier...but you will have to take some core science and math courses), having a few good internships, and getting some experience in the health field. you'll have to take the MCAT (med school standardized test) and probably the GRE (generic grad school standardized test)...but that's a few years down the road.
bottom line: med schools don't care about your ACT score. a good ACT score MIGHT help you get into a good college, which MIGHT impress med schools when you go to apply. and it looks like you're going to get a good score, so no worries!