At what age can a child decide to live with the noncustodial parent in Indiana

18, when the child becomes an adult.

A "child" can never decide. Until one is 18 (and no longer a child) they cannot make the decision. Only a court can decide custody. As a child gets older their preference may be given more an more weight byy the court and some states have specific guidelines on the amount of weight.

This means that, if the NCP wishes to change custody they have to petition the court for a change. The court will then review the facts and make a decision.