Sorry for the late reply, I had to reach level 2 to comment :D

It's a good start, you seem to be paying attention to having highlights and some anti-aliasing in your picture. You have to be careful to make sure there aren't too many redundant colours in your palette - there seems to be two copies of the same flesh colour, two copies of the same green colour, a green colour that gets used for a single pixel, and two green colours that seem to get mixed up when you paint the 'base tone' of the hair [instead of the highlights or shadows]. I've made a quick collage showing where these discrepancies are.

It's not a glaring issue overall, but it can help your workflow if you keep track of your use of colours and trim excess/unneeded ones on a regular basis. If you have a palette showing multiple of what seems like the same colour, try radically adjusting it to see what pixels in the main picture change along with it, and you get an idea of whether there are any stragglers left that need cleaning up. Otherwise you end up like me with a dozen colours on different layers struggling to organise everything in the long run.

That's great, especially for a first attempt! Could you please submit an unscaled version of this image? Thank you!