The point is how many days after your Last period did you have intercourse. If you have  intercourse  during your periods then  you can't be pregnant.  So it makes no difference after how many days after sexual intercourse you do pregnancy test.  But if you have intercourse during the period of ovulation then even  15 days are enough to get a positive result.

Wait till u miss ur periods n then check

For accurate  results,  to be done when period  date is missed .