thats not bad at all for a first shot. there isnt much to critique since you're new to maya except that I would have probably started with a torus for the wheels. also, when you're asking for comments on your model, its good to add a wireframe shot of what your model looks like, so others can see how well you've managed your mesh and get an idea of how you arrived at the final result or help point out problems etc etc . keep it up