Could I become pregnant after intercourse on the 13th day my menstruation?

The answer: yes

Explanations:

It is possible for a woman to get pregnant after having intercourse on the 13th day of her menstrual cycle, depending on the length of her menstrual cycle and when she ovulates. Ovulation usually occurs 10 to 14 days before the start of a woman's next period. If a woman has a shorter menstrual cycle, it is more likely that she could conceive after having intercourse on the 13th day of her cycle.