The girl is sooo cute!! I like the design behind her and the space idea since it suits her. But I don't think this should be a center-focused wallpaper because her hair makes things seem unbalanced. Maybe it's just me, haha.

Also, the background seems empty like it's not finished (too much black in the bottom half). The stars are too uniform so they just look like the grain effect to me. Perhaps if there was more variety in shapes and color, they would look more like stars/galaxies.

Lastly, the sun and its glow clashes a bit with the graininess. The sun is really shiny looking and it makes me want the rest of the wallpaper to be shiny too! Anyway, with more development, this would be a very nice wallpaper!