You want the gun fit to be comfortable and the eye to be lined up with the rib and sights of the gun.
Usually this requires the pad to be rotated counter clockwise a few degrees and lowered a little so it
fits in the shoulder pocket. After each adjustment mount the gun with eyes closed and then check
the fit and alignment. HMB
Have her lift the gun up to the shooting position away from her body and pull it straight into her face, not worrying where it hits her shoulder. Then adjust the butt pad so that it is in full contact with her shoulder, at the same time when the gun is mounted. Depending on her build, that will determine the amount of rotation needed to fit comfortably. There may also be a pitch issue that might need to be addressed.