I think thats another folk tale. I think it depends on the female. Everyones body is different. Also take into consideration if the girl has been pregnant before they tend to show quicker and possibly be bigger.
I happen to fit one of the myths of carrying low and being ALL belly which is a sign of a boy. It has been confirmed that Im having a boy. Then I read other females carried the same way and have had a girl!!! (too funny) It just boils down to the mother basically.
Keep us informed I know you are anxious to find out!!!!