38 weeks tomorrow

I'll be 38 weeks tomorrow, but it doesn't sound like I'll make it to my due date.  I'm already between 2 and 3 cm dialated, and the midwife was able to touch the baby's head.  I said I hoped the baby would come in one week, and she said that was probably when the baby would come considering my rate of progress.  But it is kind of scary to think I'm almost 3 cm already considering I was 3 cm when I got to the hospital with Tobey, and it only took 4.5 hours to get to 10.  How fast is this going to be?