Hi Anthony,
A very nice composition here on not the easiest of subjects. Kids rarely stay still long enough to rack a decent shot off. Waiting for the candid moments, as you have, always tends to bring the best results.
The only thing I would say is that it looks like the focus is ever so slightly off. Ideally the eye should be the focal point and I think the camera has focused on the nose. Its easy enough done, especially if either photographer or subject move and because of the angle, you have a smaller target to aim for in this image.
I would perhaps come a fraction tighter with the crop, to remove the dark area to the left of the window frame and add a bit more contrast to the tonal range - mainly to boost the highlights a tad. I'd also add a catch light to the eye and the reflection. This adds more "life" and interest to the eye. I had a quick play in Photoshop, adding the above and some "unsharp mask" to show you an example.
Apart from these minor points, I think you have a lovely photograph here