You Don't say how old you are, but I assume on the young side. RCL caters to a wide variety of ages. Liberty is Freedom class. We got off Freedom last week and loved it. Lots to do. I must admit I am 60 but young at heart
The crowd (it was a New Years cruise) was remarkably diverse in both age and nationality. Can't say much about early seating, we always do late seating. Early does seem to be more family's with kids. They also offer Any Time dining. If you don't like your table mates you may be able to switch. But all in all Carnival ships can't hold a candle to RCL. Liberty has so much to do. I suspect you'll have a great time. Ships are beautiful and RCL is a great cruise line. Bars include Boleros for a Latin theme, Schooner Bar has a piano man, there is an English Pub, Champaign Bar, and the Viking Crown Lounge for a beautiful view and relaxing drink. It usually also has a band, but more subdued. There is also a Disco. But Boleros for some Latin music and dancing seems like a happening place.
Have a great time.