@Megan1415
Luv your cottage! 😊
I would list those as "toddler beds" in sleeping arrangements. Then I would take a photo of them folded and unfolded/made up and put a caption/description on the photos that states they are folding mini beds and available upon request. I would put this in Other Details as well.
Studio vs 1 Bedroom -
Just to note....
Your cottage is actually a Studio, not a one bedroom. The bed is in an open area in the living space; it doesn't have 4 walls and a door. To get Airbnb to recognize this is a "Studio" and not a one bedroom, remove the bedroom room and then add to the Living Room photo all the sleeping arrangements:
1 Double
2 Toddler beds
Then your sub title will be correct: Studio, 3 beds/1 bath.