Vixen, your hands are about the same size as mine, and I don't have much trouble playing the low whistles. You will, however, probably curse me for having said that once you've bought yourself a low. But don't fret! The strech IS long, but if you twist you lower hand downwards a bit, and use the parts between the first and second joint, instead of your finger tips, you'll get it inthe end.
And, yes, it'll take some getting used to, but the sound of a good low whistle is soooo nice, it'll be worth it!