I feel as though you may have started out in the wrong end at this project. When making an icon there's a bit more to take into consideration than just how accurately the drawing is full-scale. Chances are, an icon will most of the time be smaller than 100x100 pixels, which means a lot of the detail will lose significance or disappear entirely.
Instead, the focus should be on the basic composition and mood. Additionally you may want to aim for making it distinct, memorable, and significant to yourself. Sort of to compliment your online persona, so to speak.