Okla. Stat. tit. 12, § 12-177.2: Limitation of actions

Provided, any proceeding or suit or action to challenge or

vacate or reopen a judgment ratified or confirmed by this act or law

shall be commenced within six (6) months from the effective date

hereof. Unless such suit or proceeding is begun within such time,

the right to attack or challenge or question the validity of such

judgment shall be forever barred.