You have done fine to get those skin tones looking good, and the shot itself is nice and sharp. Where I have a problem is the use of flash which has produced a really hard-edged shadow under her chin. It looks like you shot indoors without any ambient light and very close to the subject.
Set the flash to -1 in this sort of situation. The whole effect of the shot is also that it is still a snap, with that open mouth and the hair hanging in front of the eye. Next time try leaning over and moving that hair from in front of her eye before shooting.
TIP: To avoid using flash for indoor portraits, try shooting the subject in natural lighting, say near a window, while turning on lamps nearby will help add a more attractive feel.