My other half got me one for xmas for leg hairs. It takes a while but they grow back less obviously and eventually go away - you do have to keep at it though. Not an instant fix at all.
Given it's an electrical pulse that's passed through (you put one pad on the area iyou wish to de-hair and another at another point on the body (all in the manua as it has to be a certain distance from the target area) perhaps worth consulting a doctor about the possible side effects of passing electricity through an older woman. Although any kit you buy will say something about that in the manual, you'd hope.