Thank you for drawing her pronounced jawline along with her other elegant features. I find a lot of artists don't draw her jawline, maybe because it doesn't fit into their conception of femininity, or because they just don't know how to draw it just right. I think it just adds to her beauty.
I noticed that you didn't include the embossed design on her neckband. Maybe you excluded it for a reason. It may be nitpicking, but in every other area of the picture you seem to have been going for painstaking accuracy, down to the individual scales on her headcrests.
I had scribbled it in a couple times but I was never happy with it. I'm not great at linework . I simplified it to something I was comfortable with, as I've done with all the clothing on these portraits, though most less noticeable than this. I wanted to focus mostly on the faces