It’s good practice for the SAT and ACT. For the moment, these college admissions tests remain very important for most students and the colleges they’re applying to. The sooner you start preparing, the more likely you are to earn a high score.
You could win a big scholarship. Students scoring in the top 5% and up may be eligible for National Merit Scholarships. Students scoring in the top 1% may be eligible for scholarships worth hundreds of thousands of dollars in the form of free college tuition, room, board, and expenses!
Your school told you so. Many high school juniors are required to take the PSAT during school hours. Schools require students to take the PSAT for the reasons above but also because administrators need a clear idea of how their students are performing relative to students at other schools.