Hey there! Nice portrait! The length isn't too bad... After all, you're maintaining the proportions of the thirds. The main issue I see with the head is that it's too narrow at the back. You're not taking the length of the skull into account, which makes the back of the head look flattened. On people without hair, the round shape of the skull is usually more noticeable. :) Remember that the skull is round rather than oval. Hope this helps!