It used to be a girl :/

So I was reading up on the forum and just doing the usual when I came across this lady who had been told up until 37+4 that she was having a girl and then at her 37week appointment the doctor confirmed its a boy!!!WHATTTT!!!Thats crazy and I can tell you how nuts its driving me!!I recent changed gyni's and im beyond that my new gyni says its a boy instead of my girl being well...a girl....I found her story crazy...at the end if her pregnancy they tell her the right gender?gahhh sometimes pregnancy is not easy right