No. That's an educated guess. In reality she has ywo weeks before and about two weeks after that she could deliver, and the baby would still be considered full-term.
My mother had a friend that was given a year to live. Cancer was taking her. Mom couldn't understand why she was still alive 13 months later. Seriously. Course though, my mom had early stages of dementia.
What are you like 9 years old
no, it depends on the developments in the last trimester, the weight of the baby, the health of the mother and baby, when the doctor is available, etc., etc., etc.
No , could be earlier or the baby could be late ..
not necessarily unless you're being induced on that day...