The attitude is right, but her arm is too thin. Also, her hand should be bigger than that, since what it seems you're trying to do is attempt foreshortening. Please correct me if I'm wrong.
If it is foreshortening, the hand should be bigger since it is the closest thing to us, and her arm should actually be less visible, practically hidden behind her hand. Other than there, there are some anatomy issues. In particular, she's too thin and her head is too big. Again, if you were going for a side shot of her torso I see what you were trying to do in making her look thin, since this is a perspective issue as well as foreshortening. The problem with the perspective here is that while we wouldn't see the width of her torso from the front, we would see it from the side, and it would be reasonably larger than that.
This causes problems with the head, which I just mentioned. The head looks bigger because her body and proportions are smaller. Overall, things like these take practice and time to get adjusted to. I suggest using reference materials and photos of people in poses that are like that, so you can understand how it works visually. When you see it visually, you'll be able to apply it technically in a better fashion.
I think you chose a pose and perspective that was too complicated for your skills to handle, at this point. You have lots of different things going on here that you're not able to take advantage of. I give you credit, though, for not taking the easy way out. You could have easily just given up and drew a pose that was easier, but you went for something more advanced, even though it was a risk, and I respect that.
Keep going.