Never shot a Kahr .40, but I have owned or shot a pretty fair selection of compact 9mm and .40's. I have found you don't get the hand numbing recoil of say, a light weight .44mag. What you do get is a lot of muzzle flip, with recoil fairly sharp with a .40. I would suggest letting her try one before purchase, as it may well be more then she is comfortable with. For an inexperienced shooter, sometimes a heavier, lesser powered pistol makes more sense, as it easier to hit accurately with, and less likely to cause flinching. The last woman I taught to shoot was having a hard time with her sub-compact Glock .40, but did well with my 9mm model 19 Glock, and in fact ended up trading her .40 for a model 19 a few days later. Downloading can work, to an extent, but you risk reliability, and lessen terminal performance.
Larry