I recently took the practice SSAT a couple months ago and I scored about around the 75th percentile. (without preparation)
What are my chances of raising my score over a whole summer and a few months?? My goal is to get in the 90th percentile. Do you think I can raise my score by attending classes once a week?? Thanks! 
Which practice SSAT did you use? Did you use actual SSATs from the Official Guide published by the actual testing company, or practice tests from some other test prep company like the Princeton Review? To get an accurate overall view of what your percentile may be, use the practice tests from SSATâs official guide. The ones made by the test prep companies are only imitations and I found that a lot of them were either harder or much easier than the actual test.
Do you think the classes will be beneficial to ** you? ** Do you have a copy of the class syllabus or what the class coversâdo they include test strategies and proper review of the concepts covered in the test?
Have you tried using test prep books yet (i.e.: Princeton Review, IvyGlobal) OR the SSATâs Official Guide? The practice tests in the Official Guide are actually written by those who make the actual SSAT, so theyâll be the closest to the âreal thingâ as you can get.
Thatâs up to you and how much effort you put into it. If you diligently work on reviewing the math, practicing reading strategies, speed reading, and reading comprehension, and learning new vocabulary words, you will be well prepared for the SSAT.
Which section(s) did you have the most trouble with?
Donât trust practice tests that much, unless theyâre from the Official SSAT book, just like @thelittleswimmer said. I took one from the Princeton Review, and placed in the 70th percentile. I walked into the test center with not much prep after that and got a 99.
So, donât freak out. The practice tests can be inaccurate.