I have answered your question in a blog post for today. Here is the link to that answer:
I was wondering if there is a minimum age requirement for the PSAT. I have students who are interested in taking it earlier than in 10th grade.
My advice is to wait.... wait until you feel like you know when "junior" year will be. You will know, because you'll be thinking about colleges, and how to apply to colleges. At that point, when you've decided it's junior year, THAT is when you take the PSAT "for real." Then let the year before that be 10th grade, and take the PSAT for fun. Taking the PSAT fun fun is really NOT a huge deal. It's more important to study for the SAT. If you have an extremely bright child, then they can raise their score on the SAT much more by actually studying for the SAT. The PSAT doesn't really increase the score much at all.
Sometimes I have a hard time giving counsel via email, and I'm not sure I've done a very good job on this answer. Remember that you can always call me during my "free office hours." These kinds of questions are the perfect "10 minute question" for my office hours. This month, the free time is Wednesdays, 1:00-2:00 Pacific Time.
My toll free number is 1-888-Lee-2Help.
If I have an 8th grader doing 9th grade work when should he take the psat for practice and for real?
Sometimes, I post something that really strikes the heart of my readers. An old post I had about measuring character qualities other than academic ones, was one of those posts.
If you're like me, you have seen a lot of headlines recently about how homeschool students have dominated national spelling and geography bees and have been awarded the best scholarships