In between SATs?

I took an SAT today in school, and I felt pretty good about it (but I also felt pretty good about my practice SATs and scored a little lower than I’d hoped). This was my first SAT, and I’ll probably take another one in May, since that usually brings up your score.
Should I start studying this month, though? I want to wait to get my scores, but if they come out near the end of March, I don’t want to be too rushed to study before the May test. I don’t want to over-study in case I actually meet my target score on this SAT, though. Thoughts on what I should do?

Start studying now. What would you regret more: studying in vein or not having enough time to study and consequently needing to take the SAT a third time?