@grey the only relevant thing it restricts is watching age restricted videos, and you can provide a selfie or a credit card number instead of your ID. if you've been diligent enough to not give google either of those things then good on you i guess. i think the overlap of people who use youtube with a signed-in account but have never paid any money to google or had a picture/video of their face anywhere that google is connected to is extremely small.
they'll probably look at the content your account is watching and compare it to the channels' demographics. if you have a significant portion of your watch time on channels who primarily have a viewer base of people under 18, then your account will be flagged if its creation date was over a certain year. unless y'all are watching fortnite and roblox videos and your google account was made like 3 years ago i think you'll be fine lol.
the only thing that sucks is that it has come to this. that parents really cannot figure out how the fuck to parent their kids so someone else has to step in and do it instead. this has happened with plenty of other things in the past though so i'm not surprised in the slightest.