First, you're not 'just a little 14 year old boy'. I starting programming in BASIC when I was 9, and switched to objc/cocoa at 14, I'm 15 now. I have written and sold apps for palm OS, I have written and put up for downloading apps for the mac, and am currently working on the iphone. Age isn't a limiting factor.
As for where you should start, I'd say start with desktop mac programming. It's the same language and almost the same frameworks, but there's a lot more tutorials and docs on desktop mac programming than iphone.
First you should look at
http://www.cprogramming.com. It's old and you probably shouldn't bother actually doing the activities, but at least read through them and answer the quiz questions.
After that, move on to becomeanxcoder at
http://www.cocoalab.com. It starts you from scratch, teaching you the very basics of programming in objc/cocoa on the desktop. It's a little old and things have changed a bit but it's not too hard to figure out.
When you've finished that, you'll probably feel ready to go learn a bunch more stuff, which is good. Becomeanxcoder leaves a lot to learn still, but it gives you the base you need to start. So what you need to learn now are the details. I advise a mixture of the internet (this site and google, start your own bookmark collection) and the 3rd edition of hillegasse's book, cocoa programming.
Apple's docs are the pandora's box of mac programming, IMO. I didn't understand them for the longest time, especially the docs for each class. But once I understood them, suddenly I could use whatever class I wanted without fear of messing around, trying to get it to work. If you have the same problem I did or have any other question, just shoot me an email at
lipton_lover@mac.com.
Hope that helps and good luck, Nate