I transferred from a JC so all my high school stuff was especially irrelevant. we're more or less locked into the majors we applied for, but even then I know a couple people who switched during their third year -- or else added a second major on top of their current one. college classes, majors, etc. are so mutable that there's really no point in worrying about them during high school. all that matters then is getting the GPA and SAT scores to get you where you want to go, and understanding the foundational material enough that you don't flounder when you get there.