If she’s not spayed and was around intact males she is likely pregnant and her sides will begin to bulge around the 5-week mark. Nipples pink up around day 21. Pregnancy lasts between 63-68 days. You have time to prepare!
May I ask why you want her to have a litter? Do you have homes set up for all her kittens and will vaccinate and deworm them and if possible fix them before they leave?