@Arcaik 18 is the closest there is to a standard, due to the Convention on the Rights of the Child, which establishes 18 as the default age of majority (but stll allows it to be overridden by local laws). A curious example of another value leaking is how, because 16 used to be the age of majority in Netherlands for a long time, a lot of medical guidelines for trans youths, even in other countries, used to adopt 16 as an explicit age that a person would be able to consent to their gender (until the GOPnik bullies decided to start picking on trans women and children after the Oberge fell).
@lerxst @david_chisnall