The EU is rolling out the EUDI system this year where citizens can verify their age (>16, >18, >21) without revealing any personal information. This is a solved problem over there.
There are some long Github threads in the official repo along with a PDF[1] of cryptographer's feedback about the privacy issues. Also covered in this[2] article.
This is unlike BBS+ which supports unlinkability and which was even recommended by GSMA Europe to such address downsides. In the Github discussions there seems to be pushback by those officially involved that claim BBS+ isn't compatible with EUDI[3] and there seems to be some plateauing of any progress advancing it.
[1] https://github.com/eu-digital-identity-wallet/eudi-doc-archi...
[2] https://news.dyne.org/the-problems-of-european-digital-ident...
[3] https://github.com/eu-digital-identity-wallet/eudi-doc-archi...
These massive privacy issues have all been raised on their Github, and the team behind the wallet have been ignoring them.
you can also introduce some jitter like changing age range only once a week/month/year for everyone
If you run into a liquor store yelling "Im finally 18, here's proof." that's on you?
1 it requires DOB
2 it requires DOB to be accurate
But also, knowing someone's birthday without trying it to other information greatly reduces the risk of harm.
You can be 30 and verify >16 today and >18 tomorrow, obviously without being 18.