Curious about chances

So I just started my birth control on a Sunday and am currently on Day 13. My bf came inside of me for the first time on Day 11 and again today. I’m not necessarily freakin out or stressing and neither is he. But what are the chances? I just ask because I know a couple people who got pregnant on the pill after months of taking it 🤷🏻‍♀️

P.S. I’m taking Tri-Sprintec to help regulate. I’ve been PG before but it wasn’t successful 😬