No. This is not the way.
> give parents the ABILITY to advertise the users age to browsers, apps and everything in between.
Accounts and Applications to services that provide countent are set to a country-specific age rating restrictions (PG, 12+, 18+, whatever). That's it.
None of the things you mentioned have any point to concern themself with the age or age-bracket of the user in front of the device. This can and will be abused. This is very obvious. Think about it.
Why should the applications get to decide if they are appropriate for a particular age? Shouldn't that be up to the parent? I shouldn't need to tell my kid: "Well, to use this compiler software, you need to set your age to 18 temporarily, because some product manager 3,000 miles away decided to rate it 18+. But, set it back to age 13 afterwards because you shouldn't be on adult sites." It's stupid.
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