The proportions aren't that bad, thus, the overall style of your art is quite ( or maybe too much ) good for a beginner.
One hint: pay attention to the legs. The legs are the point where you miss the proportion the most... I mean, I think the legs are the only thing you don't draw well. You know the right proportion of the hand's height ( the middle of the thighs ), but you MUST remember that thighs are veeeeeeery long if you properly notice. Look yourself on a mirror, and see how long your own thighs are. Remember, as well, that the length of all the way from the knee to the soles is equal to the thigh's lenght.
Oh, another thing. To make your characters look young, make their legs correspond to at least 40% of their height.
Your hair-drawing style is almost like mine.