I think also that it is socially conditionned. That is, any society can actually make higher or lower such age not from a legal point of view but factually.
If we were thinking about the age of maturity of anybody at any time as the lowest possible, I think we would have to specify to what effect, if it is to deal with practical sides of life, like money transactions, work and business, froma sexual point of view, from the point of view of reproduction, etc.
I think most settings of that age are conventional and each has its own traps and do not respond to the individual but to the average, that is, it may work for some people but not necessarily for all and in all aspects.
Today I am afraid, there is a lot of weight put on the rights fo the younger persons but not enough on their duties, which is wrong, rights and duties must go parallel, be balanced. That creates plenty of problems.
Also there is the contradiction between setting high ages for marriage, while setting ery low ages for sexual consent.
Salaam