Interesting. I would have thought given that pitchers tend to gain more mph between 16 and 17 than between 17 and 18 there would be a tendency to follow a younger pitcher at a given velocity. Of course if a 17yo junior is throwing 3 or 4 mph faster than a 16yo junior going into their junior season one would go with the bird in hand, although I'd think there'd be a tendency to keep an eye on the younger one as a possibility for the late signing period just in case the younger one made some strides in ability over the next year plus.
In the end, a player has to demonstrate they have the talent to play at the next level whatever age they may be, and despite my focus on velocity there's also more than velocity involved as long as the velocity is there.
Given his velocity right now as a fairly young 16yo, I expect CASon's best chance at signing with a D1 as a freshman will be during the late signing period next year as it would be a stretch for him to add enough velocity prior to then. If not he should be able to go the JC route if he's set on D1 or play at a lower level than D1.