Sonographers gender telling

Amna
Hello everyone
I had my ultrasound at 19 weeks exactly and came to know that I am having a girl. 
At time of telling gender at the end of US the sonographer was saying that she thinks she saw boy parts in the beginning. And then tried many times ( due to baby position) to find out gender. Meanwhile she kept on saying I saw boy initially but now I can't find out precisely and after many tries she said its girl and then again 2 or 3 checks she repeated its girl. 
I am confused why she was changing her statement every min. 
What do you think ladies a sonographer can be wrong or confused ?