12
It’s classed at the 12th week until you get to 13 weeks. Also 13 weeks is the second trimester.
As soon as you hit 12, you’re then in your 13th week. However, you haven’t had a completed 13 weeks yet, if that makes any sense? Like how, when your baby is in their first year before they’re 1. That’s how I think about it, but honestly I don’t think about it like that, I just say I’m 12 weeks until I hit the next full week.
You are over 12 weeks therefore second trimester now :)
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
Im 14 + 5 and I would say I'm 14 weeks still.