Cute pic!
In the color version I see a ton of cyan in her hair, especially around her part. It looks like the original SOOC version was a little underexposed and then brought up in post-process. The cyan color cast does run throughout, so maybe pull a little of that out in curves. I'd warm it up a tad too. Her teeth look pretty overdone as well - did you try and whiten them further in process? If so, it's a little too much.
The B&W conversion is pretty well done. Her skin tone is a little muddy in that one, and I think it needs a tad bit more contrast, but overall, the whites are white and it looks pretty good.
Both look over-sharpened though to me. Are you working on a color calibrated monitor?