The ACT and SAT tests you can take anytime you want. Some kids even take them in Middle School, though that is probably a bad idea. You usually should take them in the summer after sophomore year or in the fall of Jr year. That way if you want to take them again you will have plenty of time to prepare.

Check the website of collegeboard.com for more details.

There are lots of websites that have info on the PSATs.

The ACT and SAT are both offered throughout the school year to students of any age. It is a good idea to take the test early so that you can get the feel for test conditions, time limits, and things of that nature. If your scores are acceptable, great. If you want to improve, you have time to do so.

Good luck in high school!