Why not try a ship suited to your age group e.g. Ocean Village. No set time for meals etc.etc.
I would suggest that Sea Princess might be more suitable for you at your age. ... Neil.
Id suggest royal carribean independence of the seas loads of fun things to do flow rider rock climbing golf yes golf loads of great bars discos ive sailed ventura DONT DO IT ! read the reviews but id reccomend IOTS.
Or Ocean Village. They have 2 ships in the caribbean and are specifically aimed at your age group so the entertainment, nightclub etc. will be to your liking and it is laid back with no formal evenings (unlike sea princess). My next choice, for you, would be Sea Princess.