Baby coming early ?

alexia

I went to my regular check up today I'm 24 weeks and 4 days. well when she measured him he's measuring 27 weeks and 2 days and she mentioned his heart rate was a little fast . She told me not to freak out that she will monitor it . But I'm measuring 3 weeks ahead anyone have a similar situation and baby came around dud date ? Or come earlier than due date . This is my 3 baby .