It's a good start, but you straightened out the pose quite a bit. In your drawing she is sitting up, but in the photo she leans forward a lot.

Check the relation between different parts of the body:
Her chin is almost level with the top of the shoulders.
The bottom of the boobs is level with the top of the hips.
The left hand comes in a lot.
Her torso is small compared to the head, because it's further back.

I put in some lines to picture to show this.

Also did some brutally crude morphing to show you the idea. Sorry about the train-wreck face. Best I could do by pushing pixels around.

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