I don’t know what you have been told about the SATs but they are not a test of innate abilities. They are a test of how you can respond to a set of questions of a certain type. MOST IMPORTANTLY, as others have mentioned - it covers material that you have not yet studied.
The PSAT 8/9, which is the SAT, modified for 8th and 9th grade, has 1120 at the 91st percentile for freshmen.The SAT is somewhat harder, even for the material which you are expected to know, so you are doing decently well.
Practicing on test taking is not a bad idea, but the most important factor which will increase your scores by 300-400 points, even without prep, is simply learning the material in class.
If you gain mastery of the material, and learn how SAT tests are written, and develop the right strategies for testing, you’ll do well. However, there is no way to figure out just how well you will do on the SATs, not this early.