For what I counted, you're currently using 9 colors.
I suggest for the last two color a blueish gray shade to balance between the light gray and the peachish-white. For the last color, another shade of pink, or purple. This is all for shading.
I'm fairly good with shading and can do so when you're finished.
Look how "Final Fantasy IV: The After Years" used their colors. Square-Enix used shades of blue instead of all shades of gray.
If you changed up the whites to a blueish like Square did, you might see the eyes a bit more. It doesn't have to be as dark a blue as I used, but you can see where that extra shade would differentiate between the shades of blue in the hair and the white.
Heres an example where I toned it up a bit.
-------Yours-----------------Mine--------
-----------------------------------------
I further went into this and added an extra shade to the hair leaving 1 extra color. I did two possibilities, a shade to the skin color or a shade to the clothing. You choose.
------Clothes----------------Skin--------