Should I get rid of my double bed or should I keep the way it is?

when i was little my parents had a storage room which is now my sister's room, and we used to sleep in the same bed and now my parents asked me if i wanted to change the bed into a single bed, bunk bed, or futon bed a href="http://www.google.com.au/images?hl=en&q=futon%20bunk%20bed&um=1&ie=UTF-8&source=og&sa=N&tab=wi" rel="nofollow"http://www.google.com.au/images?hl=en&q=…/a ___________-what do u guys think? and my room isn't really small but not that big either