This is worse than the California one. Since this applies to all Internet-capable operating systems, it's effectively forcing people to utter their age bracket in order to communicate digitally, which is compelled speech - a violation of the First Amendment.

Here's an idea for the lawmakers that actually want to solve the digital parenting problem: fix the mobile OS duopoly with antitrust. Most kids only know how to use touchscreen devices. If you force mobile hardware vendors to ship smartphones without an OS, then we will get plenty of forks of Android and even entirely new OSes as a result of natural demand, some of which will be toy OSes with all of the child features built in. We'll also get scam-proof OSes for the elderly as a bonus. There is no good reason for the entire population to use the same OS.