If Gavin started wrestling "late" than what is "normal"? Kindergarten? I don't even want to think about what you would consider "early," because I would guess it involves still being in the womb or even pre-conception. Cue the joke parade. I apologize in advance for opening the door.
I don't think many people are underselling his potential as a high end recruit. He is a stud. He will be a multiple time AA I have no doubts. However, he is the oldest kid I have ever heard of being eligible to compete in High School and he has had elite coaching now for close to a decade. The learning curve for every athlete slows down at some point and generally speaking, age, physical maturity, elite workout partners, and access to high level coaching are major contributors to accelerating that learning curve. Gavin already has had those happen to some degree or another, so, just like many other top recruits nowadays, he might not have too much growth left to reach his ceiling. However, make no qualms about it, his floor is already pretty darn high and while I think he isn't on the level as Lee, Fix, or Suriano, he is going to come in and compete for AA status right out of the gate eventually.