It looks like you are having some sharpness problems on this shot. The shutter speed is too low and you shot with the fastest aperture. Since you were in auto mode I guess this is expected.
I'd recommend you try a different exposure mode like aperture priority. Stop the lens down to f5.6-8 and adjust the ISO so that it's shutter is no slower than 1/60. Don't be afraid of higher ISO. On your camera ISO1600 is just getting started. Yes more light would be better, but the f-stop and shutter speed are causing bigger problems here.
Place your focus point directly over her nearest eye.
Give it a another try! Keep shooting! You'll get it