In addition to the legality and the wishes of field owners, and the ability of ASC to set it's rules regarding classifieds-
I simply would not want to play with 14 year olds. There, I said it.
Playing milsim. Simulating combat. We have our kit and our guns and we go down to the right type of belt and what not. The last thing I want is a child in the field.
I've thought of international humanitarian law regarding the use of child soldiers enough, the last place I care to think of it is down range of my gun.
Just my two cents.