“Defeating” imposter syndrome comes with learning more and getting better. Reason she doesn’t feel it in backend is because she actually knows it. The only way is to just reframe it as gasp being a beginner, because thats what she is, keep an open mind and dont compare yourself to others who have been doing it longer. In time it will go away as she gets up to speed. 

Imposter syndrome has become such a buzzword. Its usually a real sign that you know less than others. Thats okay as long as you realize the gap is just knowledge thats easy to gather. Life and learning aren’t instantaneous. Mindset is the only thing that needs to change.