My D and her top classmates all took the SAT in 8th grade for the practice. They studied for the exam with their math and english teachers and IMO helped them understand how to study for and take a long, timed test. The only real downside is that some of the math problems had not been covered in their 8th grade honors math classes yet. As a junior in the fall she will take the PSAT and ACT and we will see which test she does better in, most likely will take the actual SAT in spring?