Baby growing 1 weeks and 6 days ahead

When I got my first ultrasound at 7 weeks baby was growing right on schedule. At my 12 weeks appointment baby was growing 1 weeks and a few days ahead of due date, went to go find out my sex of the baby (I paid for it) at 16 weeks to find that my baby was growing at 1 weeks and 3 days ahead. Now I had a ultrasound at 22 weeks to find that my baby is growing 1 weeks and 6 days ahead. Could this mean I'll have my baby sooner then my due date??? What does this mean???