Most of us have been there. I've had a very few start at 16 weeks, most around 5 to 6 months, but my blue egg layers that I got hatching eggs from a breeder did not start until 9 months. She couldn't understand, most of hers started laying at 5 to 6 months. Once I got hatching eggs from them and incubated them their daughters started at 5 to 6 months. There is no logical reason those three waited for nine months but they did.
It's probably just a short matter of time for yours with those bright red combs. They look ready. But it is possible they are already laying and are hiding a nest from you. If you look at the vents you can tell if they are laying or at least are real close. If the vent is pink, soft, and damp-looking she is laying or just a few days away. If the vent is tight and dry you need to be patient.
If the vent is soft and pink, you might try locking that one up for a few days to see if you get an egg. My guess at that age is that they just haven't started, but you can check the vents and see what you think.