It would be possible to implement age verification in a way that would somewhat work and that would be to use the correct crypto on an government issued ID card. Crypto where the OS (or a website) can ask the card: "Is the holder of that card over X years old y/n?" and the card would just answer with a binary yes no question without exposing any other data while still checking the government signature.
Obviously that won't stop motivated teens from taking their parents ID cards or similar mechanisms. Thst means any system that likes to prevent that needs to additionally ensure the identity of the card holder. And then you create a privacy nightmare.
So my proposal would be to accept that nothing is ever perfect and just use the card and ensure that system works as well as it could.
Of course "card " is a standin for all manner of hardware that can do it, including phones.
Obviously that won't stop motivated teens from taking their parents ID cards or similar mechanisms. Thst means any system that likes to prevent that needs to additionally ensure the identity of the card holder. And then you create a privacy nightmare.
So my proposal would be to accept that nothing is ever perfect and just use the card and ensure that system works as well as it could.
Of course "card " is a standin for all manner of hardware that can do it, including phones.