When i can get pregnant if my period is always after 21 days and my period always last 5 days . what's the best time for me to get pregnant .

8-11 days: Your cycle is a bit short. I usually recommend 11 days.

Check ovulation kit: Wen cycles vary from the usual 28 days, it is usually in the length of time from the start of bleeding until you ovulate. However, this is not always the case. You need to get an ovulation predictor kit at your local drug store. They are easy to use and can let you know when you are ovulating (which is the most likely time to get pregnant).