I want to be a runner too!

I want to be a runner. I never really been great at running but I want to change that now. I want to be one of those people who wakes up early before work and just goes out and runs like 5 miles...just because they can. I'm jealous I'll admit it. I want that freedom where my body (my mind) doesn't stop me. I am very impressed by runners. Therefore, I want to be one! When I go to the gym I usually pick the elliptical over the treadmill. But now I'm addicted to the challenge of running...trying to be faster or go further than I have. I don't try both at once though. I can run for two miles without stopping at treadmill speed of 5...which is about 24 minutes. This is great because before two weeks ago I don't think I've ever even tried to run two miles. I would like to try a 5k. There is one on December 5th that I am tempted to sign up for. That's more than a month away. I am nervous because I don't know if I will really be ready for it. At the same time all I need to do is add another mile and some change to my current run and I'll be there....at the same time that seems like a lot and nothing. There's also one in January that I am more leaning toward signing up for just because it's further away. Is there anyone out there reading this that has any advice on how to prepare for a 5k? Or that went from being a non-runner to a runner?