Answer:
You can take the SAT anytime in your life and prepare start preparing for it, be it online, practice tests it will help you improve the score. I am an SAT tutor with a site www.examville.com, there so many students who already have started preparing for SAT while in college, so that they can score well. Practice tests, Live classes, Interactive sessions with students and teachers helps a lot and gives a fair idea about the SAT. Good Luck and Do well!