"Hmm?" Han Shin tilted his head, ignoring the coughing sound from Sierra. "Ah, she didn't mean how long it's been since you were awakened as a guide, but when you started working," he explained to the guide, since it was a common mistake.
A lot of people awakened their ability from a young age, including all three founders of Trinity guild. And once awakened, they would be sent to schools that specialized in espers, to better nurture their talent and prepare them for the trial. Of course, there was an option of not going, and not all espers wanted to work in the dungeon or security-related matters. But even those that were willing, wouldn't be able to officially work until they were eighteen.