I recently shared with the class how my 21-month-old daughter has taken to sleeping on the floor. Last week, she learned to climb out of her crib, so we removed one side and added a mesh rail, but she's chosen to sleep on a pile of blankets and pillows not in her crib instead. I suppose it's not ideal, but going off of the comments on the post and other things I've read, it's certainly not all that uncommon. She's safe; she's well-rested; she's happy. And that makes me happy.
However, I had a realization last night when I was puttering around the house, picking up toys, etc., after I put her to bed. I wasn't ready for her to be in a bed (or, in her case, a floor). Babies sleep in cribs; big girls sleep in beds.