That requires trusting a government with a power that is likely to be abused.

But they already know my age (and my address, and my SS#, and my income, and a whole bunch of other stuff).

They don't know your full behavioral profile. They also may be willing to sell that data to third parties who use it for nefarious purposes.

The power to tell people how old someone is?

The power of correlating your real ID with your browsing activity on the internet.

I mean, as much as I don't want the Government to be able to do that, I don't want private industry to be able to do that even more tbh. Though both options are pretty horrendous privacy-wise.

Until recently I felt the opposite way -- what they could do with that was more targeted advertising. The government currently in power is demonstrating that they can do far worse, and plans to.