Major in something you enjoy, not necessarily in science. Your pre-med courses will more than prepare you for the MCAT, and it will make you a more well-rounded person to learn about other stuff besides science, unless of course, you love science. It is intersting that you so adamantly state your career wishes: EM or surgery, when they are so different in nature. Enjoy college and do well. Study hard and take it one step at a time. When the time comes, you'll decide on a specialty, but, you are very far away from such concerns. Whatever you do, do not miss out on growing as a person during college; It is more important than you can imagine. Although it is important to be ambitious and set goals, the most important quality you absolutely need to be a good doctor is to first, be a good person.
With respect to coursework: don't take too many sciences at once and avoid orgo with physics. Also try to take calculus before physics.
Good luck!