Her mother, Patricia Spann, 44, will appear in court for the same charge in January.
And when they married in 2016, Patricia Ann allegedly convinced her daughter they weren't breaking the law.
Misty Spann pleaded guilty to incest and will be on probation with two of those years under the supervision of the Oklahoma Department of Corrections. The mother reportedly told authorities that she and Misty "hit it off".
In March 2016, the mother-daughter duo took their taboo relationship to the next level and got hitched, according to a marriage license application.
Their marriage didn't come to light until a Oklahoma Department of Human Services child welfare investigator did an inquiry that led her to believe that the couple was having an incestuous relationship, according to Tulsa World. She also once married her son Cody, who claims both he and his sister were manipulated by Patricia Ann.
Their incestuous marriage was discovered by authorities during a child welfare investigation, the Associated Press reported.
The mother told the DHS worker she "had looked into it" and felt no laws had been violated "because her name was no longer listed on Misty's birth certificate", police reported.
A woman has been found guilty of incest after marrying her mother.
Patricia married her son to keep him from going overseas since he was in the military, Smith said.
The marriage between Misty and her mother was annulled October 12, six weeks after Misty filed for an annulment "by reason of illegality and fraud", the Tulsa World reports. For you to want to put your own daughter through this, what kind of person are you?
"I think she's just a sick, twisted individual that has something messed up in her head", Cody, 25, told PEOPLE last September.
She was sentenced to 10 years of probation and ordered to get counseling. Was she an adult?