Well we are late in getting to this. Hopefully a critique will still be of use to you. Please take my words in the spirit in which they are given - the desire to assist you in improving your work.
Overall the piece is reasonably composed. The figure placement in the frame is just off center and I think that always adds interest.
The overall impression the painting gives is - flat. The lighting on the figure gives the impression of flatness, the rendering of the forms are not fully fleshed out and thus appear flat. Even the paint appears in the photo to have uniformly "sunken in" and gives the impression of chalkyness. Let's address each in turn:
The lighting in the painting appears inconsistent. Now, I am not sure how you painted this - if you took a photo in the session and then painted from that, or if this is from sketches and memory? Regardless, there is some indication that the light is coming from a high angle and to the left of the form as you were to face her. I sort of feel as if in your reference, the light was not terribly strongly defined...or as if there are multiple lights as there is a fairly strong cast shadow under the chin, but not under the nose...and the shadow under the chin is showing reflected light from below. Similarly, if the light source was high and left, the it feels as if the light on the hat, would fall away more and the backside of the hat, and the side of her face and neck would be more in shadow.
Weak lighting, multiple light sources, or sources of light reflection can be difficult to manage in a portrait.
The rendering of the forms is fairly loose and sketchy overall, and somewhat tighter in the face. It feels as if you have not fully expressed the values that would have been present in the live form...not sure if your reference captured these or not...the hat seems to have a fairly strong highlight, whereas the nose is missing a highlight that might have helped you turn the form...brows and forehead look flat. The highlights on the cheeks look inconsistent to the light source. The flesh tones are a bit muddy.
From a warm/cool flesh impression, remember that where flesh is "fleshy" it will be filled with blood - hence warm. Where flesh stretches over bone or sinks into hollows, it will usually appear cool. The very warm patch over her left eye feels very warm for flesh stretched over bone and specifically jumped out at me. Your edge of the face is good and not too sharp to the background. If you cooled your flesh tones as you approached the edge it would make the form turn away better.
Clothing. This appears very sketchy and needs more work to give the impression of fabric and form.
Since I mentioned the background...it is too jumbled, too "left vs. right", and too stark and harsh for the image in my opinion. It fights the subject. The lost edge on her far shoulder is nicely done.
As for the paint. This could well be the photograph, but that at least gives the impression that the paint is chalky and looks "sunken in" and potentially underbound. That is, if this is painted in oil. If you are working in acrylic, then that can be the look acrylic paints give without any additives. If either of these is the case, then please disregard. Otherwise, look to your method of paint application.
And so, I do hope this helps! If anything I have said is not clear, please ask. Happy to have further conversation.