Hey wickedtuna, Nice job on this drawing. Despite the proportion issues you already noticed, it is a pretty good likeness. @Magnus Marshall touched on the value structure of your drawing, and I wanted to elaborate on that a little more. First of all, the skin is almost never going to be the white of the paper (unless it's a high key image) so you need to make sure the skin has a local value that represents the skin in general. If you notice, her skin is mostly in shadow. If you compare the value on the top of the nose to the value of her cheek, you will see that the cheek is much darker. Comparing values is very important to get our rendering to feel like it represents the reference. Also, keep in mind that there are hard and soft edges. Cast shadows tend to be hard and form shadows are soft edged. This helps sell the idea of form and is an important element to our rendering. I did a quick paint over to show you some of what I'm talking about, I hope it helps :)

You definitely have nice looking lines and dynamic shapes, here's some things that might help. You've spotted the issue with the jaw's proportions, I would add that it could be longer and rounder too. It might help you to imagine the overall mass in a box; your's is quite square whereas the reference is taller and more rectangular. You're not far off but the hair/forehead could take up more room vertically too. The halfway point between the top of her head and bottom of her chin is roughly at her eyebrow or the top of her nose. Finally, the value groups in your drawing could be improved. You've made a good start with the groups to the left and right of the face in the hair. Try blurring your eyes/squinting at he reference and you'll notice only a small part of her face is in light. The rest is in shadow including her neck. I've drawn on a couple of examples of how you can group values into shapes in the future. I hope this helps and please ask if anything needs explaining better. Well done, keep drawing!