Yes. And that's awesome. Assurance is provided by the fact that only the device owner can set the user's age. If you buy your own just select over 18. If someone else buys it for you, they can select your age or choose to fake it and you need their password to change it.

Crucially, no privacy is violated, but children are still protected. This not only protects children but also disarms any argument that we need to protect the children. It's great actually.