To start this is very cute, I really love the colors, especially the ones in her hair. The coloring is very nice although it could stand a little refinement in the realm of smoothness but overall it's still really well done.
While the pose is very energetic there are some anatomy issues that need to be addressed and they're most centered in her arms. While everything else is pretty solid the arms are too short for her body. Her hands are also very off and therefore awkward looking. They seem to be all fingers, I suggest drawing a place specifically for the palm before attaching the fingers to help give them more of a sense of solidity.
Her ears are very cute but they don't look right where they attach to the head. They're blending into the hair even though they'd realistically be separate from it unless her ears were made of hair. Instead it would look better to have them be sticking out of the hair with pieces going over it to hide where they connect to the skull.
On a very small final note when you have a character with their mouth open like that it tends to look more natural to have a bit of their teeth showing.
Very cute though, the background and stars look just superb as well.
I will always admire the amount of colors you put into your work >w< not to mention your over the top adorableness and i like what you did with the black frame with her popping out, it adds a nice contrast with overall eye fun