Quick Google search found 2 groups will use USA ages, PG and FPN. PG (Perfect Game) is one of the big baseball showcase programs but looks like they do some softball in the midwest. FPN runs showcases in the New England area. Nothing new from Alliance, PGF, D1, or other softball programs. There may be an impact on tryouts with teams not being sure which way to go or just playing it safe and using straight birth year. Maybe others will put something out as Championships are wrapping up.
PG softball is ran by the director who hired me with USSSA. He was the Midwest VP and eventually National Director for USSSA Fastpitch and got approached by PG to start up their softball offering starting within the Midwest states right before Covid. He is getting small traction primarily in the areas he ran events in prior is about it. PG is baseballs equivalent of PGF in that there majority focus is on high end/showcase baseball events.
Honestly, something like this age change would have probably been something he would have been onboard with the minute it was explained to him as he authored a lot of the good changes and great programs that are prevalent in USSSA still to this day.
FPN I know nothing about as I rarely ever hear about the New England states.
I do not know that any date change is going to be perfect. Like Kymn stated below, school age restrictions vary from state to state and district to district.
I do know that we will have our work cut out for us to convince some of our directors at the higher level to get behind the change. Our region boss also runs Indiana. He has almost completely wiped out all of his competition especially USA Softball. They have national board members in their state who can not get events off the ground at all. Almost all of their hot spots have parks that have contacted our guy to put events in their parks so they do not sit empty every weekend in the summer like they have the past two seasons. So to convince him that changing to something that USA is doing is going to fall on deaf ears.
Texas is another spot that USSSA primarily is the dominant sanction. Other than metro Dallas, USA is small in the other metro areas of the state. Our TX state director is also the Southern Region director so another one who will be hard to convince when he has not much competition from them in his state.
Iowa is another where we are the dominant sanction. Guess who the Midwest Regional boss is? Same with Kansas. Guess where our National director's home state is and where he operates his tournament company out of?
I have explained to them all, in Ohio I am behind enemy lines with reference to USA Softball with the former National director living in the middle of the state. I do my best to get market share but will probably never "own" the state like some of our other state directors do.