In the United States, the age of majority back in the 19th century was 21 years of age, and of which, those that were under the age of 21, were therefore effectively in the care of their parents, who thereby controlled their earnings, their income, and essentially their freedom. It was not until the 21st century, that the age of majority for both male and female, was lowered to the age of 18, yet since that time, the United States for certain activities, such as in the buying of cigarettes, or in the drinking of alcohol, has raised the age back to 21, therefore providing what appears to be a situation, in which people at the age of 18, while being franchised to vote, as well as being subject to signing up for the military and therefore dying for their country in the service to it, somehow aren't considered worthy to legally smoke or drink, despite their majority age.
The age of majority is of critical importance for all those that desire the fruits of their labor, of which, not every parent so made, is a good parent for a given child, and hence some children are denied that which they fairly labored for by their parents who have the legal right to that labor, simply on the basis of their child's age, and not upon the content of that child's character or any fair consideration of the effort put forth to earn that money, by the person so making it.
The fact that the age of majority was lowered to the age of 18, should be something that is absolutely consistent throughout every avenue of those that have therefore become the age of majority; this is so needed so that there are not, in effect, two classes of adults -- which is a bastardization of what being an adult actually is, and makes for extremely poor law, along with it being absolutely inconsistent; for either the age of majority is 18 or it is 21, or some other age, but it should not be one age for this and another age for that.
Those that are adults often enjoy being in the catbird seat, and so, some of these are selfishly not all that interested in sharing power, or in ceding power; but rather they seem to prefer to spend inordinate amounts of time, writing about and talking about, how they need to protect our youth, or see to it that our youth are not subject to that which is inimical to them, which perhaps demonstrates the best of intentions, but such intentions often seem to serve a much more underhanded purpose, which is the turning back of the clock to those days when patriarchy was the iron law of the land.
People are defined by the decisions that they make, good or bad, and right or wrong, of which to believe that somehow, mere age, brings wisdom, is insulting to all those that have intelligence, sensibility, maturity, and discernment, but aren't old. To believe, that somehow, father knows best, is belied by all the fathers that don't know best; and further to believe that the government of supposed do-gooders knows what is best is fundamentally flawed for their governmental actions seem to indicate the very opposite. Those that that have reached the age of majority are entitled to all of their rights, not some sort of subset to such, for true liberty deserves no less than 100% of it, or it isn't liberty.