Hey man Dont spend too much time stressing over "being limited," just draw what you enjoy drawing! So this isn't too bad, the head is a little big and the proportions aren't perfect but you already knew that. Seeing as it is present in both your digital and traditional drawings I thought I would offer up my opinion on your choice of shading. I say opinion and not critique because its one of those things that is hard to label as "right" or "wrong." So, most of the time manga style drawings dont use a lot of shading. In my experience they tend to stick to cell shading or just very very minimal shading. The kind of shading that you seem to be aiming for is more often found in realism or semi-realism. And even then there are still parts of the drawing that are just white. Dont be afraid of white space, it can be your friend. Anyway, I think it would be helpful for you to reevaluate how you are shading your drawings; maybe look up artists that you admire and see how they do it? That is almost always helpful and a good source of inspiration. If you decide to stick with the sort of "shade everything" thing you have going on, it might be helpful to try aiming for a smoother look where the pencil lines are less visible.
Good luck and looking forward to more of your work