Good job, I can tell you're paying particular attention to anatomy and shading, good work there. The proportions feel pretty solid and well done. The texturing could be better, the flat background and texture overlay on the shorts look a little cheap, always remember when using texture overlay, that less is more. If you make it too strong it becomes apparent that it's being used to 'fake' detail you didn't create, whereas if you use it like a garnish on a meal, as a light enhancement, the whole piece will life. Great work, keep it up!

You certainly can shade well, posing is done fine,
Some of the proportion seem a little awry.
Its too finely shaded though, thats the problem, there is no texture at ALL.
Clothing can use a bit more work, the shorts don't have any cloth wrinkles that you would expect them too have. The transparency also ruins it a little in the shorts.
Keep painting though, for a first upload its pretty decent and shows potential.