|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
On this site, as in life, you are either an adult or a minor. Therefore, I have a bias when I write this essay, as does everyone who writes an essay on this topic. Whether you are an adult or a minor, please don't use that as a reason to disregard what is written herein. Doing so puts me and anyone else who publishes his or her thoughts on ageism in a sort of "damned-if-you-are, damned-if-you-aren't" situation.
While age is a good indicator of the average maturity of a person in that age group, it is not fail-safe. For the average retiree, maturity is way up there; for the average teenager, well, it isn't. The burden to make proof available to support or disprove this rule-of-thumb is on individual editors' shoulders. To clarify, it is not necessarily the burden of the editor to assemble the data into an argument but merely to make them available for use in one. An answer to a question is not a sufficient argument on its own grounds; contributions, reputation, and overall demeanor must be checked to verify it.
This is to say, editors—both young and old—should be judged on conduct and not on age, within reason.