Well let me start with this:
I was also afraid at the beginning... Now I had taken 3 cruises and next summer I will take my fourth this is an addiction LOL.
So my first impression is that someone or something had make you believe you will be on a dish washer,
Actually a Cruise ship will shake a little but is no way near a plane with turbulence just be prepared, a little Dramamine and that’s all!!!
As for the 3000 people you will not even notice,
Believe me there is so many things to do you will not have time:
• FOOD!!! buffets high class style
• Ice skating in many cruises of RCCL
• Activities like golf and the shows wow!!! is way better than a hotel
• The restaurants and the services are A+
So give it a try believe me you will not regret it…