The detail is really nice for such a small figure. I'd maybe try to bring down the color count. You currently have 57 different colors on your piece. Try re-using the same colors in different areas to cut down on the amount you have. It otherwise looks well done though.
I agree with adscomics! Just have one base skin tone and have multiple lighter and darker variants for shading (three of each maybe?) and another three colors for the underwear and hair (since they are pretty close in color).
Also, I must add that the character seems stiff. Maybe have a knee slightly bent and the shoulders lowered?
A tip would be to first draw the spine and then draw the character based on that.
Don't get me wrong, for a first pixel art it is really good, and the fact that the character is almost naked leads me to think that equipment will be a thing in your game, so most of that stiffness will be covered.