I'd want to buy this, I might have to wait for the selection of the eyes then I'll decide, might want to look up something like ' cat eye sketch ' or something.

Looks good so far. Adding some minute asymmetry in the design would be nice (While keeping the major forms symmetrical of course).

I noticed that you have a highlight on your preview but not on your flat. I'm guessing you couldn't get the highlight to look nice on your flat? It'd be nice if you got the highlight on the flat, but that's something I could never do myself. I ended up guessing that in real life the highlight depends on your angle of view so it can't be done on a flat. I may be wrong there though.

For the eyes. Personally I find it helps to think of a glass ball with light shining on it. Most of the light will form a small pool down near the bottom (That goes for both the iris and the white part around it). If you want it to look anime-ish it may help to draw in the shadows from the eyelids and make the bottom of the eye a bit darker too (To imply the roundness of the eye). If you want to make it cat-like you can use sharp pupils. Also I'd suggest playing around with the shape of the eye highlight to see what looks nice. Maybe something like using a star, heart, square, or oval instead of a circle for your highlight will add more character to it.

Really like the design of the hair. Good job on that.