Your analogy about children and the state is interesting. Certainly, some governmental regulation can increase our freedoms, as you demonstrate. But Nature has not made it so. It must be because our culture has delayed psychological adulthood. I think because you end high school at 18, and end college at 21.
Innocence is great - for children.
But a 13 year old is not a child. Many parents do not want their 13 year old reading Judy Blume books. That's fine, if you want to keep your adult at the psychological level of a child. I think the world should not be held back from people who are 13. And then, at age 15, you should be able to drink, drive, vote,and work full time.