Nope ... My mom had 3 kids my sis and I were 4 weeks early and my little brother was 6 weeks early and I went 5 days past my due date soooooo no it's not genetics
“If you're a first-time mom, look at your mother's childbirth history. "If your mother delivered one week past her due date, you are more apt to deliver one week past your due date as well," explains Fredric D. Frigoletto, Jr., M.D., chief of obstetrics at Massachusetts General Hospital, in Boston.”
Here's the link to the full article, hope it helps!
http://www.parents.com/pregnancy/giving-birth/labor-and-delivery/the-truth-about-due-dates/?esrc=nwASprenatal_Wk30&email=6555557617
Every single women and pregnancy is different. theres no way to predict when you will have your baby especially not based off someone elses experience family or not. My mom had two on time one 2 weeks early and one almost a week late. Every baby will arrive when they are ready
My mother had both her children at 34 weeks, and even though I began to have consistent contractions and began to dilate at 35 I carried the full 40 weeks with my daughter.
It could just as easily be something about her build. Is she saying that her own mother had all *her* kids a week after they are due, and her mother's mother? If not, she is probably just emoting for you. I don't think you will inherit her tendency to have late babies.
Dependsz on tha person...good luck :)