I applaud the effort you put in to this drawing, and I have nothing but praise but I like to start with the negative aspects before going to positive ones.
The bad: When I looked at Fluttershy's tail where it met the cloak it felt like the cloak was part of the tail almost like a tangent of some sort. I would try maybe having the corner of that cloak on that side stick out a bit. That way a disconnection between both objects are more clearly defined.
Just one bad thing thing, I almost mistook her right shoulder as being almost 2x longer than her left but looking it over again it could be just because of how her right leg is posed so it decided to over look it.
The good: The context is cute and the expression Fluttershy has is very good. It shows that she feels out of her element and is embarrassed about it. The shading is well done aside form maybe where the tail meets the cloak in the lower right quadrant. and and the softness of the overall image makes it very easy on the eyes.
Keep up the good work. I'm not one of the best art critics in fact I am still learning how after a couple years but I do know how helpful it is to at least get an honest attempt at critiquing on DA.