Child decides to go and live with step mother

I have full custody of my 3 children, all 17 years of age. They will be juniors in High School this year, so they should graduate when they are 19. They all are doing well at HS, A’s and B’s. If one child decides to live with her step mother, against my and her Bio mother’s wishes, what are the legal ramifications? Do I owe child support? What other consequences does this scenario have?

Even though this child is 17, she is still a minor and the stepmother lacks standing to pursue custody. Since there will be no legal custody to the stepmom, you will not owe any duty of child support either.