What makes a runner?

I have never been an athlete. I've been a concert pianist, a bank teller, a secretary, and now I'm a mama. But anyone can run, right? That's what I tell myself, at least. I mean, how hard is it to jog down the street? Any idiot can do it - I certainly qualify.

However, it's the mental strength where I truly suffer. Sure, I've never had big muscles or a six-pack, but that's never kept me back from anything I've wanted to do. But I am seriously struggling with the idea of pushing myself farther than I'm used to going. I think it's hard to run when I have a side cramp. If my legs are tired, I want to quit. I believe this thinking may be the one and only thing keeping me from being a "runner". In fact--I hate to even admit it, but for the sake of keeping it real--I just finished two miles on the treadmill, only 1.2 of it spent running. I've run two miles before. I ran two miles last Monday. It was comfortable, not terrible. So why not today? Why do I quit when there's no good reason to do so? I suppose that will be my ultimate measure of improvement: not the distance my feet can cover, but the will power I can muster.

For the sake of my self-esteem, I'm going to believe that what makes a runner is simply running. I forced myself onto the treadmill, even though the laundry is piled high, I have errands to run, bills to pay, and a desk to uncover... I ran, therefore I am a runner. And I'll run again tomorrow. Eventually I'll get tougher, right?