Having moved from a Canon G5 to a 30D to a 60D to a 5D3 in 2 years, I can tell you first hand the level of options "grows" dramatically at each of the steps. To wit: the 60D user manual (English) is 324 pages (PDF from Canon), whereas the 5D3 is 404 pages (Canon PDF)! I -still- haven't figured out/found the need for perhaps 25% of the features on the 60D. I'm sure the 5D3 will be my last camera. Hopefully, I'll fully understand and be able to utilize it to its fullest before someone inherits it.
As a former mainframe computer consultant with more than 50 years of taking pictures behind me, it is mind-boggling all the options available on a 5D3 compared to a simple point and shoot....or 35mm. Back in the film days, there wasn't much more to deal with than focus, shutter speed, aperture (f-stop), film type and speed (WB & ISO, today), and flash or no flash. Oh yea...optional motor drive on some cameras. The 5D3 has perhaps 25 screens of 5-6 options each, many with 5-6 options under that, a myriad of AF modes, focus point selections, customizable shooting modes, and much more. Going from zero to a 5D3 would be impossible for this old guy. I'd be stuck in the "Scene Intelligent Auto" for life if I started there!
Bottom line...I'd start simple. Start with a good entry level camera like a Rebel T3i (great price at
B&H right now
B&H Shopping Cart | B&H Photo Video ) and learn the basics first. The key is to outgrow the capabilities of the camera...not buy everything in sight and get overwhelmed trying to use it.
One more thought..."full frame" is overrated in my book. There's nothing that says full frame cameras take better pictures than crop bodies. It's all about the photographer, not the box with glass on the front.