Despite the pressure, it's important to keep in mind that your major will not define your Dartmouth career that's the beauty of a liberal arts education, after all. I've learned a ton of stuff at Dartmouth outside of my major, like how to order the perfect FoCo sandwich, how to look cute in an 80s prom dress and what it's like to be so cold I can't feel my face.
So do yourself a favor and relax. Let's get real you'll probably change your major at least five times before senior Spring anyway.