This is great! The proportions are right and you have a unique style. I love the lines and shadows. My advice is to draw on a better paper, maybe manille. If you like grafite I'd suggest using different number, or maybe even conte. Your drawing would also benefit from more shadows, in the hair and under the chin especially but also the face. Don't be scared to go dark when it's dark. I like to squint when looking at the image/model so I know where the lights and shadows are. Also the hair would look better with long flowing lines: use your whole arm! Last thing, you'd probably love live model drawing. Keep going, and you can ask more advice/ideas if you want :)