I assume at that age and where you are, there is no shortage of more competitive options for her daughter. Leagues with mandatory playing requirements aren't where champions are made.
Yes, this girl is also on an AAU team and middle school team (that this mom happens to coach). I let her know I thought those are better environments for more serious work.
What style does the high school these girls are going to play? I coach my daughter's 6th grade team and last year I ran a 1-3-1 trap and ball screen offense to an undefeated record in a lower league but got smoked in our 3 "seeding" game before christmas against mid level 1st division teams playing the same way.
After soul searching all Christmas break I finally did what I should have been doing all along and switch to man to man defense and the pass & cut motion offense that the local High School program plays. We have lost a couple of games to teams we beat last year mainly due to poor defense but in the long run it will greatly benefit the girls that want to play in high school, which my daughter does.
The biggest thing I have learned about myself in coaching is I am not nearly as competitive as I thought I was - I can't believe how many coaches will hardly play some their players in a Rec league. That is the absolute beauty of a position less offense, you don't get caught up in who "has to be in" or if some one doesn't know their role because it is all the same.
Letting 12 year old girls stand around in zone vs a team where maybe 1 or 2 girls on the other team can make a shot from outside 10 feet makes winning easy but that is about it.