Hello we are new to the forum. I know a bit about herding with shelties, I will help anyway I can.
Does Amber display behaviors that would lean you toward herding, some I use are a tendency to grab onto pantlegs strongly, or possibly alot of toy drive. I have also used tame ducks to herding instinct test.
You would start by having her 'herding instinct tested' by a trainer who knows shelties, and how they work and think. This would be on docile 'school' sheep which are accustomed to dogs in training.
Sometimes it can take several times being exposed to livestock for the dog to 'turn on' - like a light bulb going off and the instinct kicking in.
May I ask what state you are located in?
Hope I've been of some help,
thanks!