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.