Welcome
I'm a beginner too here, so I don't pretend to give you great help.
good job with that picture, I like how you've used the colours. but I have something to say on proportions. the first thing I notice is the shape of the shoulders. actually, I don't know you, so I can't really say how your shoulders are, but those look so unnatural.
usually, shoulders are three heads large:
I'm not saying you have to draw them three heads large, I'm the first that doesn't. and, uh...try to make them a bit less rounded, especially the shaded one.
sorry if I made mistakes with english
I'm still studying it