Every pregnancy is different and you are still very early. I would call your ob with your concerns since this is usual for you
Some women do not have changes early on. And it can happen all of a sudden. I was 1 cm for over 4 weeks and then went into labor and went the rest of the way in a day. My baby was 10 days late though. So, try not to worry about this. You may go over your 40 weeks but that is very common especially if it is your first pregnancy. good luck