You really did an amazing drawing. I love how you apply some details on this portrait; like on the eyes you apply details on the iris and the lens. The nose is believable and have dimension as well as the mouth. I like how you draw the hair so smooth and how you apply some folds on her hijab as well.
The only thing that improvements is that the hair have to be darker in certain areas with the mid tone and the highlight in order to create some volumes and add some shadows where the folds where on her hijab so it can have some depth and it brings out.
Your a very talented artist and I really love your drawing, just keep on practicing and keep on drawing my friend .