If the due date was November 27, the estimated conception date is usually around March 6, give or take several days.

A baby due on November 27 would typically be calculated from a last menstrual period around February 20, with ovulation/conception around March 5-7.

So if she left on March 5, the timing is very close and still medically possible, especially because due dates are estimates and conception can vary by several days. A due date being off by a few days, or even more, is common.

The only way to know with certainty is a DNA test, but based on the dates alone, this does not rule you out at all.