All the questions you've asked are fair game for public discussion here in the forums. We have lots of people who are just getting started, coming back to electronics after a few decades of doing other things, or trying to pick up new tools and techniques. The community is friendly, and we have a strict "be excellent to each other" policy.
WRT buying hardware, obviously we'd like you to buy ours.. not only for the profit motive, but because we put a lot of effort into making things work. Our prices represent an investment in quality, reliability, research, and sometimes negotiation with the manufacturers for things you can't get in catalog parts. We don't support hardware from other vendors because we don't know what choices they've made in selecting components, and sourcing parts from different suppliers can make a difference in how a device works. We support our stuff, Sparkfun supports their stuff, SainSmart supports their stuff, etc.
WRT your "will I be able to do this?" apprehension, my experienced opinion leans strongly toward: yes.
We see kids learning to solder and write code before they're out of elementary school: http://sylviashow.com
The question isn't "can I learn it?" but rather "can I put aside my fear of not being good enough to do the actual learning?" If so, you can learn as much as you want.
On top of that, electronics and software are gregarious hobbies. More often than not, the people with the most experience are the ones who enjoy helping newcomers most. Getting information isn't a problem, though getting us to shut up can be.
WRT the starter kit best for you, I'd suggest one of these two:
The Arduino is a good platform for learning how to make code and hardware work together. The learning curve is fairly gentle, but you won't outgrow it. Even when you learn enough to work with more sophisticated hardware, it's a handy tool and the programmable-hardware equivalent to a scratchpad.
For now, don't worry about specific applications. Just enjoy making the LEDs blink. That's something else you'll never outgrow. Work through the example circuits in the tutorials, and get familiar with the basic parts and how they fit together.
For a book recommendation, I'd suggest this one: http://www.adafruit.com/products/517
Forrest Mims has been writing books to capture the interest of electronics beginners since the 1970s. He gives you just enough theory to understand what the parts are doing, then gives you a cookbook of circuits to build, play with, and learn from. I don't know another writer who captures the fun of electronics better than he does.
When you void a product warranty, you give up your right to sue the manufacturer if something goes wrong and accept full responsibility for whatever happens next. And then you truly own the product.