There's no way to tell how long before you go into labor. Some people start dilating early (say 35 weeks) but don't go into labor until 41 weeks. It could be 2 weeks, it could be 4 weeks, it could be 6 weeks. Try not to think about it, it'll happen when it happens.

This is true. There's just no way to know. I am 34 weeks and dialated to 1-2cm and have been for almost a week now. My doc's are treating me for preterm labor assuming I will deliver early, but have also explained to me that I could even end up being over due. (not likely, but possible) I have always heard that once you get to 3-4 cm you are more in the active stages of labor, but some women go from 1-4 rather quickly while others take weeks. When is your next appointment? Good luck.

With my first son I was dialated 6cms and they sent me home and two days later my water broke...

With my daughter I had an irratated utarus and it kept thinking it was in labor for almost two weeks before my water broke.