When did you tell your boss

Jessica

I’m currently 15 +2 and was gonna tell my boss at our 1:1 today that I was expecting and would probably only be working through end of November, but we ran out of time and he had to run... our next meeting isn’t until in 3 weeks at which point I’ll be 18 weeks... do you think I should wait until then to tell him or just schedule a short ad-hoc meeting before? How far along were you when you told your boss?