Not sure I agree with some here. My son is playing 11u right now and he's not only attended one high school showcase (worked - catching bullpens and the home run derby), has been invited to a second this coming year as a player, but also made the regional cut for 12u Team USA and played in the NTIS games. Is he an elite player? No. Does he work hard and get opportunities? Yes. So far he has 6 high school programs wanting him to enter their Prep programs. Yet, he's only a 6th grader. I'm with PGStaff.. Waste of time going to national events at an early age? Never. But some kids handle pressure differently than others.. only you know what's best.
Great to hear how awesome your son is, but the OP's question and thread topic was about PG showcases, a lot different than what you are talking about. Of course the local USA NTIS stuff is great. My son did that as well when he was 13 and faired well. Congrats and enjoy the recruiting process for his big HS decision.