My Wife and I are not 30 somethings but we don't seekout Sleepy Old Folks Cruises!
We Love ships like Celebrity Equinox we sailed on to the med. last year BUT we also like BIG ships like Oasis and Freedom of the Seas for their amazing Experience of so much to Do and See. These Ships offer so much and are a Destination in themselves.
IF you don't like sharing your Ship with Thousands of other Cruisers (of All Ages) then they will Not be for you.
A Mega Ship spreads out the large number of Guests and we never did feel crowded or had to wait for anything,even leaving and returning to the Ship at the Ports of Call were done swiftly and moving so many People Quickly is a Royal Caribbean Specialty.
Our Cabin was the Quietest we have ever had on any Ship and the Bed was really Comfortable.
The Variety of Food offered in both the Windjammer and the Main Dining Room made meals a Pleasure.
All the Staff we encountered were Friendly and Welcoming without being "In your Face" like some other Cruise Lines that we have experienced where the Lower Price of the Cruise is made up for by Staff constantly Trying to Sell You every FrooFroo Drink and sticking a Camera in your Face every 15 seconds like Carnival.
When you review a Ship you are think about taking look at what kind of Propulsion System it has. Why?
Most Royal and Celebrity Ships built in the last 10 years use a combination Electric Motor/propeller System suspended below the Ship instead of the Old Fashioned Shaft/propeller system used by a lot of Ships (especially Carnival owned Ships Built in Italy) and the difference is that with the Pod Drive system there is Very Little Vibration and noise shaking the ship. We were on a New Carnival Ship out of Long Beach CA a few years ago where the shaking was so bad the plates and Silverware on our Table in the Main Dining Room were dancing off the Table! That same ship not long after that had an Engine Fire and lost Power and had to be Towed back to San Diego with passengers sweating in the Dark eating food flown in by the Coast Guard!
Stick with Ships built in Finland and Germany!