Nice shot of her on the back of her mount! It has a great flow to it. Watch out for tangents, like her scarf to the mount's back, her knee to its shoulder, and her toe to the line of its belly. Also, compositionally, you might consider something more in the lower right to guide the eye back around to the left and towards the mount's face and the hero. And adding some more room at the top so that her head isn't so close to the edge of the canvas.
Anyhow, great work so far. Did you ever pick a color scheme?