When should I take my Pregnancy test?

Patient: Hi there!I’m sure you get these sort of questions regularly, so here’s another: On New Years Day I had sex for the first time, unprotected. It only lasted for 8 minutes or so and he did not come inside of me. I know this because I watched him finish afterwards. My last period was around December 12th or 13th of 2011 and normally i take a good 30 days (give or take a few) before I ovulate again. My questions are:When should I take a test?Can I take one this coming weekend, as conception usually occurs within 5-7 days of intercourse?What is the likelihood of my being pregnant, since he did not come inside of me?That last question is purely to calm my nerves; I am 16 years and, typical, I’ve made a mistake.Thank you so much for your help, it is greatly appreciated!