i like the lighting.
only thing is. is she a musician or is she just using the guitar as a prop? i think you need to include the whole guitar in the picture.
I agree, the lighting is great. Nice soft light on her face that creates a nice ratio...and the hair light coming in from behind is a great touch, especially as it's not something you would expect to see in an outdoor snap shop.
I do think that her bare arms are a bit of a distraction from her face. The first one is OK but in the 2nd one, her right arm has almost become a subject all on it's own.