Nice job for your first build. Whilst there were some areas in North Africa that got a little muddy (usually near oasis) the boys are right about the amount you have on your vehicle, but not to worry. Mud usually congregates around the track area, mudguards, rear hull, etc. If the vehicle is following closely behind another, mud will be thrown up all over the front hull, and depending how high, the turret might get a splash. The track face will usuallt have mud in teh recessed areas, but the tread plate/riser/cleats would be relatively clean - just watch a bulldozer operate next time you see one.
You might consider a little mud in the spoked area of the road wheels, as the tracks would not scrape that away.
Unless the vehicle is still travelling in thick mud, the face of the road wheels would be a muddy colour, but rolling over the tracks would ensure only a thin flat layer of mud would adhere.
Thanks for showing us the pics.