Since you're still a freshman, toooootally do not worry about it because you'll score so much higher during junior year. That said, doing SAT math prep starting now is not a bad idea because come junior year, SAT math will be very familiar/easy
.
However, your best bet with a good SAT score is keeping up with all your classes, like actually "learning" math and not just memorizing formulas and stuff before a test and forgetting it all afterwards. Also, take the most challenging classes you can, like AP's. Starting sophomore year, I took AP courses in english language and composition, english lit, world history, american history, bio, and chem, and honors geometry/pre-cal classes. I got a 2340 on my first try with 2 weeks of SAT prep (all math prep because it was my weaker area, and practice exams). AP english classes really boost your verbal scores because AP exam questions are so much harder than SAT ones
. Oh, and AP's are also great for SAT II exams like bio and chem (jokes compared to the AP bio & chem exams).
Definitely don't pay for prep courses, it's unnecessary spending, but you seem to know that
. You have a great head start (my friends and I all started thinking about the SAT during junior year), you can finish a ton of prep books in 2-3 years
. But best thing about the US is their schools/classes, so take advantage of that. Now that I'm not in the US anymore I mainly have to self-teach to learn and it sucks.