You don't mention where you live, but if you are in the northern hemisphere, we are entering into shortening days...and that is working against you.
Pullets need 12 hours of uninterrupted light to trigger the pituitary to send hormones to the ovary to begin egg formation. It takes 14 consistent hours to produce regular laying.
For pullets hatched in mid to late summer, that presents a problem as often there isn't enough light in the fall time when they come of age to trigger lay.
Commercial high production lines, such as Red Sex Links and the Leghorns, often start laying anyway as their lines have been manipulated for more sensitive pituitary glands. They generally come to lay by 20 weeks like clock work no matter what...but also the commercial growers put them in lighted buildings.
You've got more "heritage" type birds that take a bit longer to mature, and they are maturing in shortening daylight.
That means they may not lay until spring unless you place them on a lighting schedule now...which will take a while to kick in too.
So it may be a while.
LofMc