The Order didn't place a lot of limits on those who could apply for their examination. When it came to age as long as you had 20 years before you were at death's door you could try out for their tests. Even though the younger you were, the better your odds of breaking through due to the strong vitality associated with a young age, that only applied to the early stages of cultivation, and that aspect could be remedied with some treasures.
There were a lot of talents that go unburied because they lacked the necessary resources to unearth that talent. It was why the Order never cared much for age and were loose in their entry requirements to the point that they would even allow someone without a cultivation base to take their examination.