Yep, I love to run, most of the time it's job oriented running, but I have been known to do 26 miles for the hell of it. Take it slow in the beginning. You should get to where you can walk at a fairly quick pace for 2 miles before you start jogging. Then, start with the same distance but do walk, jog, walk drills. Walk for a minute, jog for 20-30 seconds and then walk for another minute until you complete the distance. Once you can comfortably complete the distance start gradually increasing your jog time and decreasing your walk time until you are having trouble with the jog. When that time comes, back off on the jog time a bit and stick with that for a bit to get your body used to it. Then start adding distance maybe 1/4 mile at a time. I'm not sure of your age, but I would say you will be able to jog at an easy pace for 3K by summer if you stick to it. By the way, you will also want to throw a lot of stretching and some mild strength training in there as well. For strength training the best three exercises for working a majority of your muscles are: Pushups (chest, back and core), Squats (all leg muscles, and rear end), and bicycle crunches (core) I think you can go the the ACE, American Council on Exercise, website for demonstrations on how to do these three properly. The most important part is to not push yourself too hard to where you get too sore and then get discouraged.
Bill