We moved Curtis out around 18 months. We wanted him to be well transitioned before Dustin came and had to use the crib. I LOVE having him in his big boy bed. His is a little toddlers bed. He comes out after sleeping and naps and cuddles in my bed. He used to fight staying in his bed, but he learned quickly and we have no issues. Haven't for a long time. He fell out a couple times but it's super close to the floor so either he kept sleeping or needed some snuggles and went back to sleep. I also loved finding him sleeping in weird places hahaha. But we also kept his door closed (not tightly) so he would stay in his room.
But I don't see any harm in keeping her in her crib as long as you want. We needed the crib for Dustin and I actually really preferred him being able to come and go