how long after unprotected sex does it take to be pregnant

I had unprotected sex with a friend nov 6-12 2016 and am now 9 weeks pregnant . (Jan 20) When did I conceive? How long does it take to get pregnant after unprotected sex? My <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnancy app</a> says my first week of pregnancy was November 19th