Good luck! I have started (and stopped) running many times. I would encourage you to go very slow, and also to get out there in 2-3 days and run a whole damn mile. I am pretty certain you can do it. (If you go slow.)

If you pay attention to which part of your body is under the most strain when you run, you will be able to identify what is your "problem point" or your limiting agent. For most people it is actually their lungs; if you are gasping and out of breath, you are going too fast. If you are gasping and out of breath but your legs feel mostly okay, then lung strength/capacity is your weak spot. Or if you can keep breathing just fine but your legs are awfully weak and painful, they are your weak spot.

the important thing is to train to the weak spot. So if it's your lungs, you want to run slow enough that you don't run out of breath. If it's your legs, I guess you would have to build distance to build those muscles, before you would be able to see how fast you could go with your lung capacity.

What I like to remember is that humans were made to run. We aren't very fast, but humans are THE marathon-running animal. We were built for stamina and we were built to run for long periods - I mean, "were built" or "evolved," you know. We weren't cheetahs who take out their prey with insane, but short-lived, speed chases. We had endurance. We would follow our prey patiently until we wore it down. Running is in your nature. It's in your blood.

Everyone at Hubski can laugh at me for how unscientific and probably hog-wash-y it is but I find it inspiring :) I am a slow runner. But I am pretty convinced that if you are in reasonable shape, especially if you are young, you'll surprise yourself with your ability to complete a mile. (Just not your speed.)