When a player is new to the USTA system, they complete a self-rating survey to be issued a "self-rated" NTRP rating. Designed simply as a guide, the rating categories may be adjusted depending on your competitive ability or as your skills change. Ultimately, your rating is based on your match results.  If you are unsure of your level, choose the higher level of play.

 The NTRP system is intended to be fluid. A player's rating is intended to go up if they improve their game (or go down, if skills deteriorate). However, be realistic. Unless you were a nationally ranked junior, you'll probably never be a 5.5 or better as an adult. Just because you play for a long time, doesn't mean you're rating will continue to go up--there are many players who have played twenty years or more and are 3.5. It's not a race. The point is to find players at your level with which to enjoy a competitive game of tennis.

For more information follow the link below.

https://www.usta.com/en/home/play/adult-tennis/programs/national/about-ntrp-ratings.html