CousinEd, you are incorrect there. A creator must join Adsense as a Publisher, and then associate their YouTube channel with the Adsense account after joining the YouTube Partner Programme; there is no "automatic association" to be had. Under 18s can neither join the YouTube Partner Program or an MCN without parental permission as for business purposes, under 18s are considered unable to enter into a binding legal agreement; and a person under the age of 18 cannot start an Adsense account as I understand it.