Ladies I need advice...

My fifteen month old has been urinating less the last few days. She still has several wet diapers through the day. And at night. One poop a day. I’m noticing we’re going longer without diaper changes. I understand that the bladder increases in size. But last night she never went. She woke up with a completely dry diaper. Is this normal? Is this ok? She’s never done it and I’m just worried something else could be going on.