Wait and see what your doc says. I saw a few GPs in the early days and have seen two OBs and they all used a 28 day cycle as the basis of their calculation regardless of the length of my cycle. This gave me a EDD of 3/7 but the place that has done all my scans is insisting that I'm due 29/6. On the BB EDD calculator using my cycle length I came up with 1/7 so who knows what's right. I now tell people I'm due somewhere between the first date and the latest date.