| Six-packs are more to do with genetics and bodyfat percentage. Only a small amount of the general population will have their bodyfat distributed in such a way make a sixpack possible in the first place. And even if you're one of the lucky people who hits the right genetic combo, I think you need a bodyfat percentage of under 8%, which is very lean. Also, don't fall into the trap of thinking that crunches will make the fat on your stomach magically go away. Fat burning is not localised, otherwise everyone who ate lots would be overweight but with rock hard, lantern jaws!
But that's still no reason to not exercise, so good for you. Only thing I'd suggest is that, unless you really enjoy running on your own, you find a different form of exercise. If you just pop down your local running track today, make a mental big deal of the fact that you're going there, and run round a few times until you feel shattered, you won't go again. Your brain will fight against your willpower every time. Team sports tend to be more fun since the element of competition keeps things interesting, and there's a social side to it too. But maybe your local track has a running club you could join?  | 
