My NHR laid at 22 weeks 4 days old and she lays a large brown egg. So, I would expect you to see your first egg somewhere between 20 weeks old on the early side and 25 weeks on the late side maybe. They are individuals and will lay when they are ready.
Maggie gives me 5 eggs per week consistently and sometimes 6.
You will like the NHRs they are not as aggressive as RIRs in my opinion. Mine is a sweetie.
Looking at the picture from left to right, the eggs were laid by the following... Black Australorp, NHR, Lt Brahma and EE.