So i had unprotected sex withmy fiance october 7,2014 . the last day of my first period was september 24,2014 . my question is could i have conceived ?

Yes...: It is possible. My suggestion is to wait for your next due period and if late get a pregnancy test done.

Is Possible: It is possible that you have conceived if ovulation occurred later than the expected Oct. 2nd to 4th because menstrual cycles can vary; periods can vary between 28-35 days. If you miss your next period, recommend you do a home pregnancy test (HPT) afterwards. HPT's can detect pregnancy 7-10 days after conception. If negative, repeat HPT in 1-2 weeks. See a doctor immediately if positive.