Aft balcony cabins are extremely popular and given June is just a little ways off, it is likely you won't have a choice of decks, or even find an open aft balcony cabin (which are cat. D1 or JS
). I just looked at the June 6th cruise aboard the Serenade and there is one open D1 cabin on the aft. That could change but I wouldn't waste time debating the deck. On that ship it really isn't a huge issue, as opposed to the Voyager or Freedom class.