It will take a couple weeks after flipping to really see pistils. By 4 weeks in flower buds are quite noticeable. If you want good examples look for some grow diaries for the strain you are growing. ( eg.
https://growdiaries.com/diaries/474-pineapple-express ) As the buds develop you notice new layers of leaves and more pistils stacking on top of the previous.
Most seed vendors give something around 63 days in flower with when you actually flip to <13 hours being the start point. Some sativa strains take longer than Indica plants but many plants are hybrids now and take some where in the middle time wise. Some people like to keep the plants longer to get maximum size of bud and the strongest stone. Outside plants will often end up with mold using this strategy which destroys the bud.
It can feel like you are watching and waiting for paint to dry at times. Let the plants do their thing and have patience. It will be worth it.
