Thinking of transitioning my two year old toddler twins to a double bed. They currently sleep v well but they are in sleep suits and they are getting a bit big for them, they are tall for their age. Their bedroom is small so not much space for toddler beds so a double mattress made more sense to us. We plan to add a single bunk bed above later on when they are older. Does anyone have any experience in moving twins to a double bed?? What age did you do it? Thanks in advance.