Okla. Stat. tit. 47, § 47-6-101.1: Licenses for persons under twenty-one years of age

A. Any license issued pursuant to Sections 6-101, 6-105 or 6-

114 of this title to any person under twenty-one (21) years of age

shall be of special design, easily recognizable as the license of

such a person and shall include the language "UNDER 21" on the face

of the license.

B. When a person who has been issued a license designated to be

the license of a person under twenty-one (21) years of age attains

the age of twenty-one (21) years, said person may obtain a

replacement license without said designation upon payment of the fee

required for a duplicate license and by furnishing proof

satisfactory to Service Oklahoma or the licensed operator that said

person has attained the age of twenty-one (21) years.