Legal Question in Family Law in Montana

As long as you are a minor, you cannot legally decide where you will live. That's the bad news for you.

The good news is that courts generally will listen to the child's preference if/when the child is "old enough" to have input. Usually that means when the child is mature enough to know the difference between make-believe and real. In my experience, judges have spoken with children as young as five years old. They and the child will go into chambers, often with no one present except the child's guardian ad litem (if one exists) or with a court clerk. No parents, no attorneys, no court reporter, just the judge and the child so the child can speak freely. The judge is not required to follow the child's wishes, but often will factor in the child's wishes as it relates to "child's best interests" which is a statutory standard.

You were seeking a concrete answer, but one doesn't exist. The best way to modify the residential arrangement is to have both parents and the child agree to it. However, if good cause exists and the parents cannot informally discuss a modification, your father can file a motion to modify the parenting plan, and he can request the court allow you to speak to the judge in chambers.