If you want a great first cruise, do what we did. We sailed from San Diego, California to Miami via Panama Canal. Going through the canal is brilliant! Whole trip usually takes 2 weeks. Most of the cruise lines do that route (Calif - Florida/Carribean), so you can take your pick. We did Royal Carribean the first 2 weeks of November and effectively no kids. Princess tend to be for older people, so usually no kids and as said, P & O have kid free ships. The great thing about cruises is you do loads of miles and only unpack once!