AutoCad isn't the hardest thing to learn, quite easy in 2d formats but i wouldn't use it for 3d.
So long as you've got a good guide you can teach yourself.

Catia is a programme you should learn, good interface and has so much to it. The first being its 3D, you can also contrain your part design and a really usefull tool is seeing how the part would deform under load and wear the maximum stresses are.

I myself did a little bit of training of CAD at uni but they teach us more CATIA since it is widely used in the industry.