Sienipaa

Hi there, I'm about to go on my first cruise soon (Costa Smeralda if that makes any difference) and I have a bit of a silly question... When I want to go to the pool, do I leave my cabin in my swimwear? Is there a robe in the cabin that I can use? Or are there changing rooms in the (indoor) pool area? I feel silly asking but I'd hate to be walking around the ship in my swimwear only to realize that it's not acceptable haha!