14 CFR § 65.53

To be eligible to take the aircraft dispatcher knowledge test, a person must be at least 21 years of age.

To be eligible for an aircraft dispatcher certificate, a person must—

Be at least 23 years of age;

Be able to read, speak, write, and understand the English language;

Pass the required knowledge test prescribed by § 65.55 of this part;

Pass the required practical test prescribed by § 65.59 of this part; and

Comply with the requirements of § 65.57 of this part.