Quoting Jas ♥:" <blockquote><b>Quoting Brittanie Blokker-Brandt:</b>" ya its my tummy. Ive only gained ... [snip!] ... normally be"</blockquote> Measuring your tummy is not that accurate. I wouldn't bet on actually being 4 weeks ahead."
This...I mean, just think about how tiny a centimeter is. There's no way everybody's belly is going to be the exact same measurement to the centimeter at the same point in their pregnancy. It's just a general guideline; my midwife said that the important part is that the number is increasing, not necessarily what the number is.