Is this a good, bad, or mediocre PSAT score?

The average SAT score is about a 1500 (which is a 150 on the PSAT) so your score is just about average. The SAT is out of 2400 so there is plenty of room for improvement, but it isn't a terrible score. See if you can get a review book or take a cl before it comes time to take the SAT for real or the PSAT again (depending on your grade)