In my opinion, your helmet part is more tilted away from the viewer than the face is. So in short, you have 2 subjects with different perspectives. The circles on the head device should be more oval shaped. I'm guessing you don't want to start over, and neither would I, but I just wanted to point that out to you from a fresh pair of eyes looking at this art.
Don't give up! So far you have done a brilliant job with the face. Shading and all. I really, REALLY like the color scheme. It is very cold, which is my favorite. You did an excellent job with the creases in the lips and the shape of the eyebrows. They are not completely symmetrical, defined, or perfect so it makes her very believable. If you finish the helmet, keep up with those cool colors.
You really do have a knack for drawing people- I can always tell who it is without looking at the entire picture and without reading the title. But I think the colors blended really well together. The edges of her face are still in need of just a tad bit more editiving, but otherwise- it is magnificent. The eyes are quite expressive and I love the jawline and chin area- the darkening of the color was done very well. As for the helmet- it looks fun to be shading! So good luck! And I like the design so far.
I really like the new color scheme. The blue hues make it look very sci-fi-ish. Nice details on the face too and very nice shading, the contrast is very good! I think you should search for some metal drawing tutorials for the helmet. Drawing metal is pretty hard.