I usually get my periods around the 20's of every month. last month it was the 21st- to the 23rd or 24th. what are my most fertile days?

Fertility: You can use the first day of your last menstrual period to guide . If you use that as day one you should ovulate around day 14. Check an ovulation test kit.

Ovulation timing: The optimal time for conception is 48 hours prior to and up to the day of ovulation. Therefore, start having intercourse a couple of days prior to when you actually ovulate and have intercourse every other day for a total of five times to help ensure sperm are there when you ovulate.