Girls, hi everyone... I'm curious to know who was wrong for 15 weeks w…

Girls, hi everyone... I'm curious to know who was wrong for 15 weeks with a miscarriage. I did exactly 15 ultrasounds, the doctor said that between the legs there was a umbilical cord, she said with accuracy that it was a girl. I really want a girl but by feeling like a boy, I'm afraid I made a mistake and they said girl at the beginning because he wasn't very big there ???