You say you'll "maybe" take the SAT II in Physics? You might want to change that to a definite considering you're looking to major in that area. Have you checked the college's requirements (CoE)? Don't they require you to take the SAT II in math and a science? You'll need to prep for those as well - prep books can be found online. Also, why would you take the SAT II in Math I? That doesn't make sense to me. You should also put some serious effort into those potential leadership positions. If you aren't sure they're a lock, you might want to have a back-up plan. Also, have you entered or plan on entering any contests? Does your math league offer anything along those lines? Also, if you don't have a good relationship with your guidance counselor at this point, you need to foster one. Same with teachers you'll be approaching for letters of recommendation. And, it's never to early to start brainstorming or even working on your essays. You can easily set up an account at commonapp.org and start filling it out now. If Cornell is your number one choice and you'll be applying ED, you need to get all of your scores, letters of recommendation, etc., in the can in time, so be sure you're familiar with the application timeline. Best of luck!