A few years ago, I started jogging for the first time in my life, but I've always been a big walker. So I kicked off my first year of jogging by doing a "Resolution Run" on January 1st. My mantra for that year was, "Even if I can't run all of it, I can walk it." With that in mind, I finished two 5k, one 10k, and two half-marathons that year. I didn't have the greatest pace in the world for any of my races, but I did finish them all.
I wish you great luck and hope you have a successful run yourself! Just remember that you're not there to compete against anyone else -- you're only there to prove to yourself that you can do it.