cruise

Hi.thinking ahead,i will be 65 at Christmas and we have decided to have a holiday over Christmas for a change,not sure yet house it will go down with family,but after an awful Christmas this last one want something nice to look forward to.So question please an ideas for first time cruisers,want a casual one no dressing up and not to far so europe,maybe somewhere where we can wear t,shirts in december just for a week or so.So any ideas or advice please.many thanks.