You should be able to tackle it yourself (I have and I'm not very mechanical at all). You will need to mount the bindings in different holes in the plate, but the screws are self tapping and you don't have to drill any holes (so not at all like mounting bindings on a flat ski). Before you start, put her boot in the binding and close the binding (just as if she stepped into the binding). Find the etched marks on the steel lever at the back of the binding. The edge of the binding should fall within the etched lines when the binding is closed (that is the forward pressure check). Then move the heel piece back one notch by releasing the lever. Latch the lever and test forward pressure again and you should see that it no longer falls in the scale. Move the heel binding back to the original notch.
Unscrew the bindings from the plate (release the pressure screw in the middle first if there is one).
Decide whether you can use another set of holes to move the toe binding forward.
Decide which set of rear holes will give you the boot sole length range for the rear binding.
Adjust the metal level and notches to get the right forward pressure.