It is an older ship. We sailed on her years ago, so I am not aware of her current condition first hand.
I like the Fantasy Class ships because they are a good size.
Shorter cruises on Carnival (from other ports) can be more of a party crowd. I am not sure about California.
It isn't 5 star, but you will get your money's worth.
I would suggest that you book a cabin on Main or Upper deck. It is always better to have cabins above and below yours, if possible.
We prefer the AFT of the ship to reduce foot traffic.
Personally, I would not pay for a suite. You get the same service with an OV (Ocean View) or Interior.
Carnival does still offer 24 hour room service for free. Their pizza (at least on all the ships we have been on) has been good and is available all the time. You can get free speciality coffees in the Main Dining Room during meals. (expressos and cappicinos ...non alcoholic)
I am not a foodie...but I have found Carnival to be fairly consistant from ship to ship. I have always been pleased with their meals. (just know that the strip steak will be tough and dry on all their ships~partly my fault for eating it well done)
You are allowed to bring on soda and water, since they charge for both onboard. You are allowed to bring on a bottle of wine or champagne per adult.
If you are flexible, Carnival posts a Pack N Go rate on their website every Wednesday. You have to book it by Friday.
Hope this info helps and hope you have a wonderful cruise.