You are very close, with my baby I had recently I was 3cm dilated and I went into labor. I would ask your doctor to strip your mebranes if he hasn't already. My doctor did when I was 39 weeks and then nothing, and then he did it again at 40 weeks and a few hours later I went into labor. Also, a girl I know had her membranes stripped and she went into labor a few hours later as well.
My twins was a little different, but just ask to have your membranes stripped. That should help
it sure sounds like she is on her way, its really hard to say though. Have you had any other labour signs? such as diareah,bloody show, contractions?