I don't see that it is necessarily a problem (as in "problem with the chickens", that is, as opposed to "problem for your plans"). It's just variation. Different chickens are different. This year I have the following pullets, all hatched May 1: seven speckled sussex, of which 2-3 are laying (the first one started into lay about 2 months ago) yet the others aren't and don't even have big red combs yet; 1 golden campine hen, started laying in late August IIRC and has been going 2 out of 3 or 3 out of 4 days since then; and 2 buff chantecler pullets not laying.
It's like how books tell ya that it takes 23 hrs to produce an egg so you could never possibly have 2 or 3 eggs laid by a hen in one day, could you [yes, you sometimes can]; or how books tell ya that they need 14 hrs/day of light to lay [in reality, some chickens do, some will lay thru the winter regardless of lighting, and some seem to shut off during the winter even if given extra lighting, judging by peoples' experiences]. Etcetera.
Chickens don't read those kind of books, they just do what they do. You may have to wait a while, possibly even til late winter.
Though frankly I've found that going out and buying store eggs, while complaining bitterly about it, has an eerie tendency to provoke laying to start <vbg>
Good luck,
Pat