First babies make a difference?

Brianna
Im 36weeks pregnant & my pregnancy has been a breeze! I only had nausea the first couple weeks of pregnancy & ive had 2 yeast infections! Besides that , me & my daughter have been really healthy! I want to know why does my midwife(& some other people) say that when its your first baby you usually carry to full term or post term?(not including moms that have had problems & had to be induced early) I get the normal pregnancy symptoms like backaches , swollen feet, headaches, heartburn, acid reflux, indigestion, etc. But I really wanna know if this is true? Even though your baby chooses her own birthday lol Has anyone else went full or post term with their first baby?