-My daughter played a few years club volleyball
-My son played played several years travel baseball
-the older they get it is more of a racket with trying out, playing time, schedules, travel distance, cost, etc
-the cost gets to be significant
-coach quality can be a problem, as development for all gets traded for developing only the best, to get someone from the program recognition to get a big time college offer
-playing time can be an issue
-traveling a distance gets old, hotels involved
-how do you justify cost and time spent to other non-sport children
-no family vacations during preseason and season unless you make a tournament trip your vacation.
-kids don't have much time for any other clubs or activities, work
-oftentimes kids get burned out before they get to high school varsity level and don't play anymore
-It is fun at first, not so much as time goes on

Your 3rd grader is way to young for this.

Good luck