Hens at 1 to 1 1/2 years of age should have been laying by now. They may not be laying at the moment if you are in the northern hemisphere as the days are too short. (It takes 12 hours of continuous daylight to trigger laying, 14 hours for continuous laying).
It is hard to tell the age of a hen after she has reached maturity. You generally estimate by overall condition.
Younger hens, who have had good care, will have glossy feathers, clean scales on their legs, bright eyes, and a bright, clean comb. As a hen ages, her legs look more craggy, feathers tend to look less pristine, and the comb looks more worn. She overall just looks older. However, as implied, poor care also causes this appearance. A well cared for hen can look bright well into old age.
Most commercial layers however, look "played out" at about 3 years of age.
As to laying, you can check her back end at the vent. A laying hen will have a large, moist, "smile" looking vent. There will be 3 to 4 fingers width between her pelvic bones.
A non-laying hen will have a small, dry, puckered looking vent. There will be only 2 fingers or so between her pelvic bones.
Photos would help us determine what you may have. Pink combs at this time of year indicate not laying. If they are small and pink, you may have younger pullets who have not come into sexual maturity yet.
LofMc