Why is Gretel nervous at the end of chapter three in the boy in strip pajamas?

At the end of chapter three in "The Boy in the Striped Pajamas," Gretel feels nervous because she senses a shift in their family's circumstances, particularly with their father's new job and the move to a house near the mysterious "Camp." She is also unsettled by the oppressive atmosphere and the strict, authoritarian nature of her father's work, which she doesn't fully understand. This change creates a sense of unease and apprehension about what lies ahead for her family.