You have amazing skills! I also prefer to start with the eyes, haha (I always start with the favourite part). One, it is because they are beautiful. But maybe also because it is the eyes that express the liveliness and the emotions of the subject. After all.. they say eyes are a mirror to one's soul.

And in painting that final touch - the gloss on the eyeball, somewhere in the iris, makes the painting (or drawing in your case) so, so alive.