From: http://en.wikipedia.org/wiki/Coming_of_age
Coming of age is a young person's transition from adolescence to adulthood. The age at which this transition takes place varies in society, as does the nature of the transition. It can be a simple legal convention or can be part of a ritualistic cycle, similar to those once practiced by many societies. In the past, and in some societies today, such a change is associated with the age of sexual maturity (mid-adolescence); in others, it is associated with an age of religious responsibility. Particularly in western societies, modern legal conventions which stipulate points in late adolescence or early adulthood (most commonly 18 and 21, at which time adolescents are generally no longer considered minors and are granted the full rights of an adult) are the focus of the transition. In either case, many cultures retain ceremonies to confirm the coming of age, and significant benefits come with the change. (See also rite of passage.)
The term coming of age is also used in reference to different media such as stories, songs, movies, etc. that have a young character or characters who, by the end of the story, have developed in some way, through the undertaking of responsibility, or by learning a lesson.
Historically, the Chinese coming of age ceremony has been the Guan Li for men and the Ji Li for women. The age is usually 20 and during the ceremony, the person obtains a style name. These ceremonies are now rarely practiced in China, but there has been a recent resurgence, especially from those who are sympatheic to the Hanfu movement.