The specular highlights on the bench back and her leg draw your eye away from the all important face. This is just because the eye is naturally built to look at bright patches. I think you have made life very hard for yourself by including the hat. This gives a few problems: 1. There isn't much ambient uhder there so you are relying on your flash, 2, To get under the brim your flash is very low so you are getting the reflections on leg and bench, 3. Because the flash is so low you are perfectly lighting her nostrils and making the nose cast a big shadow into that under the hat shadow.
Also the sun is so bright with your main flash opposite there isn't much side light so she looks a little 2 dimensional.
I'd be tempted to try again without the hat, decide whether to use the sun or the flash as the main light and adjust the other down (with the flash as the main light you need to underexpose maybe as much as 3 stops to "turn the sun down"). If you use the flash as the main light bring it a bit further forward and up to lose some of that strong nose shadow.
Another option is to go in closer for a head shot and have a bit of white card as a reflector just out of shot under her chin to get some light under the brim.