The angle is unflattering. Few people (especially at wider angles) look good at the angle you've shot here. It's just not attractive.
Also, the image is underexposed. Natural light shouldn't be an "excuse" for poor lighting. If there's any light, it can be capitalized on with the proper camera settings. With a few bucks you can make a DIY reflector to get rid of the harsh shadows, or you can spend $60 and buy a reflector.
As noted you've also shot directly into the sky which is probably part of the reason the girl is so under exposed. The cameras dynamic range can't really allow for proper exposure of the sky and her face in the lighting conditions you're working with here. Solution: Shoot HDR (least favorite option IMHO) or choose your composition more carefully.
Also, work on focus. This image is way out of focus. Select the appropriate focus point to lock focus on the eyes. If you're using a small enough aperture (f/4 or above) you can use your center focus point by locking focus on the eyes and recomposing. If your aperture is too wide you'll lose your focus on the eyes when you recompose.