VRChat is 13+ as outlined in the Community Guidelines so if you see anyone under that age you’re free to report them.
Also as outlined in the Age Verification FAQ you can sign up for Age Verification even if you’re ages 13 through 17 and once you turn 18 any restrictions will be removed automatically.
There’s no way to really force people to verify in the way you’re asking unless you forced everyone to verify, something that would be incredibly expensive as these services charge per-verification.