I think what you should do is just start looking around at CAD and Cam software, and try all of the trials you can, as there isn't one that is the best at everything. I highly recommend anything from Vectric as it's just a piece of cake to learn, and that's coming from a basic newbie when I started. They have the best tutorials and VERY helpful forums as well. Just some of the nicest people over there.
Naturally the more you spend, the more options you will get, but again, try as many programs as you can to see what's right for you. Watch youtube videos, ask questions, anything to "take it all in" so that you can get comfortable with the terms of what is what when it comes to CNC.
Dave