You have a (lovely) round face - I do too - and the one time I got a short cut it looked bl*ody awful. It did absolutely nothing for me, it wasn't feminine on me, it emphasised my chin(s) and made me feel clumping and manly.
Ginnifer has got a gamine, Audrey Hepburn face, with a pointy chin, high defined cheekbones and quite elfin features. Sarah also has a thin-nish face but her cut is a lot more forgiving and suits a lot more face types.
Good on you for taking the plunge though! <admiring> I have had the same long bob for years and years, although I do like trying out different non-permanent styles like bun rings and plaits. I have not the patience or the time to be blow-drying into a style and using wax etc for definition. Your hair also looks soft (not fine, there's lots of it, but soft) and this (like mine) does not also lend itself to a sharply defined cut like Ginnifer's.
Imagine how Ginnifers looks without the mousse and the thickening spray and the wax and the hairspray.. Sarah's will also require a bit of styling, but you can probably scrunch some stying spray in the roots for a more convinient day-to-day look.
lovely cut. I had mine cut like that about 3 years ago from a short bob and everyone was and said they hated it. Now whenever anyone sees a photo from that time they say how nice it was, even DH who hated it at the time. FFS. So I would say do it and see what it looks like. It will always grow!
My hair is cut like the Sarah Harding photo linked up thread and it suits me much more than the short hair I used to have (I also have a round face.). Got mine done at Toni and Guy and it's very easy to maintain, even though I go swimming every day.