You can study for the ACT test each year of high school in varying degrees of intensity. Your freshman year, you just need to know that the ACT test is out there and to monitor your performance on in-school cumulative assessments so you get a feel for how you perform as a test-taker.
Build Up Your Testing Skills
It’s possible–depending on what kind of classes you took in middle school or how your middle school works–that high school is the first time you will take any kind of cumulative assessment, like a final or end-of-course exam. Pay attention to how you do on these tests, because the ACT is similar to a final exam in many ways: it covers topics from many years, it is a timed test, it can be hard to know what or how to study for it, and it often has some pressure attached to it.
Here are some skills you need to do well on cumulative school tests as well as the ACT:
Learn How to Be a Good Student
So the moral of the story is that you do not need to worry or do anything in particular to prep for the ACT when you are a freshman. But, you can pay attention to the things you are doing in school to get a sense of yourself as a learner: your strengths, weaknesses, your effective study methods. These skills will help you do better in school and make preparing for the ACT easier and more effective!