Reflection

One thing for sure I'd like to say is that I love how you kept the same cartoon-feel throughout the entire image, but you also relayed a message visioned in the image, and further-more in your description. Thoughts.

There are many things going on to emphasize an underlining tone such as: the reflective water - the mirror image of what this character actually feels emotionally(this can be something pinkie thinks of herself, or what she thinks others think of her. Although those theories are up to the viewer to dissect).

I can say there are many like this in their finalized form as far as water-to-mirror art goes, but you have a unique way of showcasing that. The method you've chosen, as far as your lines go, keeps the viewer reminded of nearly every step you took to finalize your art.

Overall I'm digging this, and I had to write a review, however, there are some things I'd like to give attention to in this illustration:

1- The lens flare sits perfectly to set the environment in place alongside the very well positioned clouds.
2 - Her pose is expressive yet elegant. Even those well versed in the knowledge of this character, understand the significance of her current emotion in this moment. The balloons add to this inner emotion, and even to the lore.
3 - We normally see a sickly and most times evil counterpart of pinkie, but in this you bring the word to mind; calm.