For 13 years old, your painting is pretty damn good I would say. I like your choice of colours and that they all work well together with no headache. Your painting is nice and neat and I like the bases.
Other than to just keep doing more like this, the only thing I would say is more time spent blending the hilights and shading, judging by the standard here, i\'m sure it\'s just a matter of time spent rather than ability.
How long did they take?