Minimum age of an examination candidate

The Traffic Controllers Regulation 2009 states:

Only persons who have reached the age of at least 18 years are eligible for appointment as a traffic controller, with traffic regulation tasks in the context of the profession.

It is not possible to allow a (future) traffic controller to participate in a training course and/or an exam if this person is not yet 18 years old. Under the age of 18 they are not allowed on public roads as a traffic controller, so not even to practice during the training.