Do women have there period every month on the same day as last?

The answer is: no

A woman's menstrual cycle is the regular natural change that occurs in the female reproductive system that makes pregnancy possible. The cycle is counted from the first day of a woman’s period to the day before her next period starts. For most women, the menstrual cycle lasts anywhere from 24 to 38 days. While the length of a menstrual cycle can vary from woman to woman and also from month to month for the same woman, the timing and duration of bleeding are usually about the same for each woman. Periods may last anywhere from 3 to 7 days, and typically happen every 24-38 days. So a woman's period does not happen on the same day every month.