All of the programs you mentioned are quite expensive, and if you're still on the learning curve and not studying it in school somewhere, I think it would be a bit of a waste.
Why not try something like Blender 3D
www.blender3d.org? It's opensource and multi-platform and has a great deal of functionality for you to play around with - and the principles you learn applies to other packages too - though the implementation of it may vary. There's a fair amount of tutorials and an active community (
www.elysiun.com) with people doing some amazing stuff with it.
Here's something I modelled - now I'm not showing it as an impressive example, because that it certainly isn't. All it shows it that even beginners, such as myself, can create something fairly acceptable after a few weeks of playing around with it - and it really doesn't look that bad! (Or maybe it does??)