For instance: age of sexual consent, age for legally drinking alcohol, age for driving, age for voting, age for participating in pornography
Depending on the place, each of those requires a different minimum age. Why is that? Are some activities “more adult” than others? Using USA as an example: legal drinking age is 21, legal driving age is 16, age of consent varies between 16-18.
Not asking about different countries/states having different ages, but any single place having different ages for different adult activities
To be fair, most first world countries seem to have settled on 18 for all of this. I think the wrong assumption is that the age limits are related to each-other, while they’ve been brought into law at different points in history and there hasn’t been a need to change them. There are also the environmental factors, such as the driving age in the USA probably being lower as a consequence of a car-centric culture.