Descriptions of shape [edit]. The shape of a distribution will fall somewhere in a continuum where a flat distribution might be considered central and where types of departure from this include: mounded (or unimodal), U-shaped, J-shaped, reverse-J shaped and multi-modal. A bimodal distribution would have two high points rather than one.
18 is the age. If something dangerous is going on, then you can petition the court on the matter. Courts will listen to children. But if nothing harmful is going on and your daughter just doesn't want to see her father, the court is not likely to stop the visitations.
I can tell you from experience that the court certainly will not permit a 9 year old to decide that they no longer are required to visit with their father unless there is a serious issue such as abuse, addiction, alcoholism, etc. unless the child is not safe in that environment.