Me and my husband sailed on Liberty of the Seas for our honeymoon! Overall it was a great vacation. Let me tell you about me, so you can decide if my advice would apply to you. I'm 31 and my husband is 27. He has never cruised and I have cruised twice before. Both were smaller class boats with Carnival Cruises (the fantasy in 1993 & holiday 2009).
Our experience:
The boat was beautiful and huge! I was worried about 8 days being too long of a cruise, but it gave us plenty of time to get familiar with the boat.
1283 on deck ten was great. It was under the pool deck, so every now and then you would hear large thuds, but nothing really bad. The room was what you would expect an interior cabin to be. It was convenient to everything though.