Argh! I wrote a whole long post and thought I hit submit, but I guess it never showed up! (wrote it last week!).
Anyway, here's what I said more or less:
A Komen run is a great first 5K b/c it will probably be mostly women and it's just a very supportive environment. I've done the one here in DC which is something like 65,000 participants. Mostly walkers, but still many, many runners.
Definitely try to get some road work in before, just to get a feel for it. Running on the road may technically be harder, but I like it SO much better because it is SO much more interesting!!!
On race day, try to get there ahead of time so you don't feel rushed, and be sure to hydrate well the day before (especially if it's still hot there).
I think you have enough time that if you add a minute to each training run between now and then, you'll be able to run the whole thing. And if you don't - no big deal. The most important part is that you got out there and did your first 5K!
Let us know how it goes! And apologies for the late reply.