when you get good enough you don't have to use the loomis method anymore because proportions become an intuitive process. When you start drawing ,proportions aren't intuitive which is why you need a process like the loomis method to help you

Your line quality is superb! Well done!

I think she's looking great so far, what I would suggest however, is to improve your line quality, and to maybe make the hair a little closer to the scalp. From my perspective it looks like the back of her hair is sort of like a wig barely hanging off the edge of her scalp, however this may have been intentional depending on what the hairstyle was. I think if the hair looking like that was intentional, maybe work on defining the hair a bit more to avoid any confusion. If it wasn't intentional, make the hair slightly closer to the scalp, or alternatively, make the neck at the back bigger, if you used a reference I would suggest using that as a guide to decide what to do, if you didn't use a reference, honestly its up to your imagination and what you think would work best. As for the other features, they look great so far, and are proportionally accurate. All I can suggest is to improve your line quality by not 'chicken scratching' and to draw in singular strokes. You are allowed to go over your lines, but avoid doing so where possible. The last thing I would mention is your colouring. so far you have really captured the form of the subject, however the colours are really off. The human skin is surprisingly a lot more colourful than you would automatically assume, so after you have learnt how to draw and sketch, I would suggest working on your colour. All i can suggest is to paint less to avoid bad habits, and then learn how to paint after you have finished this course. Hopefully some of this helped. Honestly, I would say for proportions your on the right track, proportions seems to be something that you're very good at. I think all you need to do is start getting on the right track for the other areas of art!