The age of consent is 16 as long as the other person is under 18. The 'gentleman' was 31 and could not have sex legally with a minor.
http://www.ageofconsent.us/state-laws/oklahoma-age-of-consent-laws/
§21‑1112. Age limitation on conviction for rape.
No person can be convicted of rape or rape by instrumentation on account of an act of sexual intercourse with anyone over the age of fourteen (14) years,
with his or her consent, unless such person was over the age of eighteen (18) years at the time of such act.