Congrats! Sometimes they like to take their time, and it's not always clear why. The past couple of years I've had two batches of the same breed of chicks, that I hatched at the exact same time (within a day of each other in April on two consecutive years). So everything aligned perfectly. And yet, the first batch started laying at the start of winter, in December, while the second batch only started at the end of February, at 10 months old! No reason why the second group should start so much later than the first... and yet they did. Chickens don't always make sense.