Cute. The one thing that stands out to me though is the water; it stays a pretty strong blue throughout. If you had it's colors desaturate into a shade closer to the sky color as it faded away, it would give some atmospheric perspective, and not be as dominant an element on the page as it is now. The viewers attention should be primarily on Carmen, 'cause it's the best thing there.
This is a nice piece! The colors blend very well, and the proportions are pretty good. However, the biggest problem I notice is that the background seems a bit disconnected. Let me explain. The water and sand are fantastic individually, but the water and sand don't slowly ease the piece into each other. I'd suggest having a lighter blue to represent the tide, instead of just one line. It would show the interaction between the two, sand and water. The shading is good, though I think raising the contrast between the colors in her stomach would make the piece really pop!