sweet shading on the face and especially the lips-good worried look

I love the "stormy" feeling this has - both in the subject and in the emotion she expresses.

reminds me of the Venus painting by....uh, someone famous. Oh well, I'm not an art historian but consider it flattery to be compared to a master.

It's alright, but I think the lighting on the face could use some work (like I mentioned on another piece). More contrast, "lighter lights, darker darks."
Also the face seems somewhat deformed to me, almost cat-like. Maybe the jaw/mouth comes out too far. If you wanted to fix it, you could try moving the neck and back of the jaw forward rather than the whole face back.