Why not lock device/accounts as minor and put onus on school and parents to ensure devices are appropriately tagged? At least for pre-teens I strongly think it shall work.
The only reasonable solution that doesn't infringe on privacy is to give parents the tools to limit their children's internet use, and presume, outside those bounds, that people are adults.
if I understand correctly it's possible to give 16+ people tokens and then they can make the signups (transactions with these tokens) and then check that the transaction is valid (that it came from some valid token without knowing which token), while also making sure that folks can't just fake spend someone's tokens -- this is how the new Monero version is going to work after all.
https://www.getmonero.org/2024/04/27/fcmps.html
Of course as others mentioned trading identities (tokens) is trivial. (As I expect not-yet-16 olds will start stealing identities/logins of older people.)
Lies every parents tell themselves. Either they will watch porn at age 11 at school or at a friend, or you isolate them from society and they resent you forever.
You can't control every aspect of your child's real life or online activities, that's naive and I don't believe you actually have children, let alone teenagers.
> Government controlled access to internet is a disgrace in any form.
And in fact it's not a "disgrace", it's outright dangerous, a ready half-step to totalitarian control. Regardless whether one trusts their current government or not, it is a threat to democracy and freedom that can be activated by any later regime.
What you don't want is to say "I can't control every part of my kid's life, so I need to government to come in and control the remainder."