Consider the drinking ages in different countries, and how they've changed over the years. There have been discussions about lowering the voting age to 16, and changes to what age is considered to be an adult for legal purposes and obligations. Not to mention the range of the age of consent throughout the world, and how it has fluctuated through the decades.
Essentially what I'm saying is that societal, moral, and ethical views vary greatly around the world, and even among individuals.
That being said, due to the emotional implications of those above, what science says about mental development is largely ignored, regardless of how "right or wrong".
This is a really controversial and tough topic of discussion, with lots of varying opinions, where finding a consensus is a bit harder than expected. Add to that the motivations of people who are fighting for or against such changes, and it makes it even more complicated.
I think the first thing that needs to happen is that sex work needs to be seen as a legitimate job, and then basic protections could be in place like any other employment. Until that happens, changing the age will remain secondary at best.
