Did you mean 1 1/2 year old? Not exactly sure about veilds but panthers should lay between 30 - 60 days max. I have had a female go nearly 60 days and still lay her eggs. If it goes that long there is something wrong with your laying bin or she is having something else going on. A vet can give oxytocin to induce egg laying before she becomes egg bound.
Unless she develops/has some physical reason for becoming eggbound (reproductive system deformity, deformed eggs, etc.) if your husbandry is right she shouldn't become eggbound.