Some polish can be hit and miss when it comes to laying. Some of my girls are great layers and others are just not that fussed! Maybe a few more weeks yet, look out for her reddening up and then it should not be too long. Remember they are bred for their looks and not for their laying ability.
Laying depends a lot on daylight hours, food and how settled they are feeling. Plus each bird is individual.
"Happiness can be found, even in the darkest of times, if only one remembers to turn on the light."