Crib 😴 sleeping

When did/planning to transition your little one to their crib?! My sweet girl is 3 months and still sleeping in a rock-n-play next to the bed. She sleeps great from 8-3 or 4, but after I feed her shell only sleep for maybe an hour and back up. I'm trying to decided if I should transition her to her crib or leave her in the rocker until she sleeps through the night?!? I've read so many different things, like don't crib sleep until 6-8 months bc baby's cognitive and mental development isn't mature until then. But then I've read as soon as possible and I know every baby is different but I just don't want to fight this when's she older. Any suggestions?