If you are teaching a beginner to drive, it is required that you are a licensed driver age 21 or over with at least one year of driving experience. This requirement is in place to ensure that the instructor has enough maturity and experience to effectively guide new drivers.
An instructor who is at least 21 years old is considered to have reached a level of responsibility suitable for the task of teaching someone to drive. Moreover, having a minimum of one year of driving experience allows the instructor to not only be familiar with driving skills but also to understand the rules of the road and how to respond to various driving situations. This combination of age and experience helps to ensure that new drivers receive quality instruction in a safe environment.
While being a licensed driver age 18 or older is significant, the additional requirement of having more driving experience adds an essential layer of safety and competence when teaching beginners. Similarly, while a commercial driving license or a specific number of years of experience might suggest a level of expertise, they do not specifically fit the criteria intended for instructing novice drivers in typical driving conditions.