Beth:
WOW, look at the progress! It is looking great! Keep refining, it is working wonderfully.
Some additional suggestions if you are amenable:
It is somewhat hard to tell from an online photo, but look at the highlights on her arms. Highlights rarely go all the way to the edge of the form - even though cameras sometimes represent them as such, so consider moving your highest highlight in from the edge and have a one or two value darkening as the arm turns away - it will be subtle, but it will make it look rounder.
Also, look at her far shoulder. See how the super bright highlight makes the shoulder appear to come forward? I know that your pic shows light coming in from the window which is why you have that effect. It works for the picture, but not as well for the painting as you are representing her outdoors. I might suggest that you tone down the highlights on the far shoulder and punch up the highlights on the closer shoulder. Don't change the form of the shirt, just punch the highlights as they are shown on the closer shoulder, and slightly gray the highlights on the far shoulder.
Dark objects in recession appear lighter and grayer. Light objects in recession appear darker and grayer. So the colors will be more intense as the form comes closer to the viewer plane and will become less intense as we recede from the viewer plane. This will apply to everything from her shirt to her knees.
Let me qualify that I am not trying to get you to paint tighter - unless that is your goal. It is my opinion, that the best paintings whether they are realistic or impressionistic, convey reality or an impression of reality by the proper placement of values regardless of brush strokes or level of detail or finish. There is a reason why Monet's purely impressionistic water lilies appear to stand out from the canvas (they are almost 3D!) - proper placement of values as the plane recedes from the viewer. He really understood color, value, and atmospheric perspective.
I hope that helps.
