Portrait of Nia Peeples

Hi I recently finished a portrait of Nia Peeples not sure how it has turned out I hope it is okay. It is the first real attempt at digital art work on the computer, I have not done many portraits before last one was a very long time ago. I could not decide how to present her so I done a few different back grounds not sure which is most suited.

Nia 1

Nia2

Nia3

Nia4

The same pictures at my deviant art page with more details (a zoomed in look)
http://mithius.deviantart.com/gallery/50668749/Nia