Not sure how many times this has been said but you really need to work on your anatomy, and being thirteen is no excuse for the art you produce, i know people at thirteen who do amazing stuff, its called practice.
I have checked through the thread though and I think your improving, but even in cartooning you need to get your proportions right, and listen to the crazy person, you need more syemtry, i recommend you get a sketchpad and go to some place with alot of shapes and variation (like a mall) and go draw whatever you see and focus less on each individual detail and more on your quality as a whole.
Good luck, ill check up on this more