I'm on my first ever pack of birth control. I had unprotected sex almost 2 weeks into my pack, and i've been pretty good with taking the pill on time. Only, 3 of the days (from the time i started to the time i had sex) I took the pill 20-40 minutes late, but I don't think that's an issue. I am now on my 3rd day of inactive pills and still haven't gotten my withdrawal bleed.