I hear ya! I have 3 BR, 6 BO, who are all the same age, born 1st week of May. The BR started squatting about 16 weeks, and two of them were getting the red comb & waddles, my other BR was a bit behind.
At 18 weeks, my biggest BR, with the reddest comb & waddle laid her first egg on Sept 1st., 5 days later the second egg arrived & 5 days after that, came the third. Two days later I got two eggs, so I knew my other BR what also has the red comb & waddle was laying. Funny thing is, that hen is my daily layer now. She has laid 5 days in a row & my other hen who started it all has taken a break.lol
The only reason I know this is, the second hen, we see her sitting in the nest box just before we find the egg.
My BO are just now started to get their waddles, small & pink or dark pink, I figure about mid Oct. I may find eggs from them, they will be about 26 - 27 weeks by then.
My 3 EE are two weeks younger than the BO, and are still pullet looking, so I figure sometime around or after Thanksgiving.
Funny thing, my 2 youngest hens are my Light Brahmas, they are a month younger than my oldest 9, but they are as big as my BO's. So with them I have no clue when to expect them to start laying.