The exact age before which Ghyllians are considered underage varies from place to place. Usually, Ghyllians are underage while they are pre-pubescent and for about a decade after, although in some places it is much younger - for instance, in one small settlement in the north of Evesque Valley, the defining age is as low as three and three quarters of a year old, due to an edict passed by some long-forgotten king. The standard age in the Xurient is also somewhat younger than most of the ages we have around here.
In any case, an underage Ghyllian is distinguished from one that is of age in that they lack several privilages. For example, in most places underage Ghyllians aren't allowed to drink alcoholic beverages, ride Equestrian Beetles or Horses, or play professional sports. Although the exact list varies by location, it is usually composed of activities that are potentially dangerous or have potentially unwanted permanent side effects, such as those that result from grenfing. Underage Ghyllians are seen as too young to be responsible for themselves, so they aren't allowed the chance to make unwise decisions that they might not want to have made when they are older and know better.
When they reach their appointed age, underage Ghyllians undergo a coming-of-age ceremony, after which they are considered to be "of age". Although these ceremonies aren't nearly as intricate and dangerous as they were when the tradition started thousands of years ago, they still contain an element of possible failure. If a Ghyllian fails their ceremony, they are allowed to try again annually until they succeed. Ghyllians who have still not come of age long after their first ceremony are often subjects of public ridicule, even after they do finally succeed.
Among other things, the ceremonies usually require the Ghyllian in question to present to their Hive-Lord some proof that they have been studying their Question and have made progress towards finding their Answer. There are also usually tests of skill, designed to challenge the Ghyllian's mental and physical prowess. After the ceremony, the Ghyllian and their peers traditionally engage in a round of spooling jumps to celebrate.
Although underage Ghyllians are usually seen as incompetent in the eyes of those who have passed their ceremonies, many of them have accomplished great things before reaching their age. For instance, Blivingdel entered Bute University three year before his own ceremony, and went on from their to have become one of the greatest intellectuals of our time.
--Dfaran L'Eniarc 23:55, 13 October 2005 (EDT)