I don't know. Societies globally agree that human babies are born prematurely and take some 16..18+ years to mature enough to take care of themselves. As an anecdote I've had both tobacco and alcohol before the legal age. Never really liked either.

My context was adults. Of course babies mustn't have the right to operate heavy machinery unsupervised, among many other things. But once society declares a person fully grown, they should have all the rights.

I'm a bit of an individualist. I understand why society, like an ant hive, would like to control some/many aspects of its constituents. But I also think that freedom isn't a mere cost, but is actually a portal to a better world overall.

Children aren't biologically capable of making sound decisions about their destiny[1]. If anything, the age could be raised.

[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621648/

I'm not sure how many children you've known. There is a huge disparity in how wise they are just as is the case with adults. I'm not sure I see the philosophical consistency of telling a sharp youth who wants to smoke that they can't while letting an unsavy adult get talked into giving up their left lung.