Fluttershy

I think you captured the picture well. The background really suits the picture greatly. The clouds were well done, and they look realistic. The rainbow is marvelous, though I couldn't see the green at first.
The color choice of pastels is comforting, and the image has a peaceful and graceful feel to it. This piece seems much like it would be from the true animation series.
I like Fluttershy's eyes, and the color is near perfect. Her wings are great, and you remembered the cutie mark. Her pose is realistic. Her chest bulges a bit, but I only noticed it on extremely close scrutinization. Her mane and tail could be longer and more like the real Fluttershy. She seems content, which is what I feel as well.
I have seen a great many of pieces like this one, so originality drops a few points. Vision is high up for its art quality and realisticness. Technique is good, for the matching of colors, though it drops a bit for lack of shading. Impact is great because it gives me a content, happy, and satisfied feel.
Overall, this piece is great and I hope others can enjoy it. You should be proud!