Not sure what Iggy is saying , but I think more likely eligible for u 15 then 2018. There is a difference. A 2017 can be eligible for u 15 but is never eligible for 2018.
No on said TLI U15 should not be allowed to go to the U15 Nationals, what is being stated is that the current group the poster keeps mentioning is ineligible according to what is stated in the USLacrosse website, also, since they will all have to confirm against the USLacrosse membership for eligibility, I believe that their U15 [NOT 2018] will be much different team.
The U-15 is the same team as the 2018 team. They are ALL 2018's this year!
