How you came to know that you got pregnant on 17/2/2009? Day of sex is not necessarily day of pregnancy. Because sperms can stay alive in female body for 5-7 days. So, even you ovulated after the 4-5 days of sex then chances of pregnancy are there. If I believe your words that you became pregnant on 17/2/2009 then your expected date of delivery can be 10th November, 2009 with few days up or down. This calculation is based on your date of conception not first day of last menstrual period.