Even if she's used to 1911s and FS pistols, it doesn't guarantee that she'll initially be successful with the Shield. Subcompact springs are much tigher than FS (or even compacts). In fact, don't be surprised if her initial groupings a Low-Left. It seems that many people transitioning from FS pistols, because of the difference in grip, etc) initially shoot Low-Left and blame the gun... or the sights being off. Lightweight Subcompacts will bring out trigger control flaws that heavier FS and even Compacts can be 'forgiving' with.
There are probably several threads about the Low-Left phenomena on the 1st 2 or 3 pages of this sub-forum. Forum Search 'Low and Left' and you get several dozen hits.