I'll be in 12th grade this upcoming school year. When is the best time for me to take the SAT?
If you're applying to college your senior year, you should take the SAT as early as possible in the fall so that test prep doesn't get in the way of the college application process. That means that you should register for the October or November test date.
If you're applying to college early decision or early action, register for the October date so that you can submit scores in time for the November application deadline. If you're applying regular decision, you could technically take the test in December or, depending on the deadlines for the schools where you plan on applying, January. However, I would try to avoid these later test dates so that your studying doesn't collide with midterms and you avoid stress about submitting scores in time. It's best to take the test in October or November and leave December and January as potential retesting dates if you mess up the first time around.