It is possible to cryptographically attest to attributes like age without revealing identity. I worked on a privacy preserving system that did this among other things. Third parties who received an attestation of some property could verify it. To be fully private, a bit more is required. Crucially, each time an attestation is provided it is made unlinkable to previous times it may have been provided. So the third par…
Besides that, why is any of that complicated stuff even needed? I know my age, and I am able to verify my age without involving any 3rd party, software, AI etc. If someone else wants to lie about their age, I am not convinced that I should need to jump through hoops and give away my own privacy as part of any of the flawed schemes supposedly intended to prevent that, as some governments are trying to push.