I'm currently working on the C25K program (just finished week 5) and I was wondering if it would be too soon to run a 5k after week 6. I did W5D3 for distance, so it would only be a little more than a mile longer. I'm just afraid I might do some damage, but it could give me a progress report and give me that little extra motivation if I can run the whole thing. I need some guidance.
Personally I would say go for it, just keep in mind that your body may not be able to do as well as you'd like so if you don't finish or don't finish as well as you'd like, don't take it too hard. I would do it as a matter of motivation. It would give you a good idea as to how well your training is going and where you need improvement. I have one planned for Sept (even though I'm only on week 2 of C25K) that is a week after I finish my program and another in late Oct. My goal is to do the best I can and use the experience as fuel for bigger and better things. You might do the same!
Give it a try. I did my first 5K after the first week of C25K and ended up walking most of it. You will be far more prepared for your first 5K than I was.
Watch your pace early on. Many people get a bit caught up in the excitement of the race and start off at a pace that just isn't sustainable for the entire race. You'll probably want to run at or near your training pace for the race if you are already doing 2 mile runs, assuming course and weather conditions are similar to your training conditions.
C25K - graduated 7/9/10
Justiceworks' JustRun 5K - 9/4/10: 24:52
American Cancer Society Walk/Run 5K - 9/19/10: 24:20