Science - related goals?

Hey, curious rising freshmen here. Typically when I stick with my gut, I turn out to be right. I have a strong passion for chemistry and biology and have been looking at some pretty competitive medical schools for college. I’ve planned out my classes and everything, but I know that anything can change between today and when I take classes at my high school. What if I find out my passion is in law and I’ve been taking classes in per-med up until junior year? Is it a good idea to plan like this before high school?