Prepare to have a blast. You will likely be addicted to cruising. First, I would advise reading the new first time cruisers board on cruise critic and the Carnival boards. Loads of info there and I don't know what I would have done without cruise critic advise. Lots more posters there too.
http://boards.cruisecritic.com/ (main page of boards)
http://boards.cruisecritic.com/forumdisplay.php?f=97 (first time cruisers)
http://boards.cruisecritic.com/forumdisplay.php?f=215 (Carnival threads)
Soda on the ship is only Coke products. We aren't Coke drinkers so we always carry on what we plan to drink. Carnival lets you carryon reasonable amounts of non-alcoholic beverages. I drink Pepsi One and usually carryon 2 12 packs and a couple 2 ltr bottles and never have a problem. I also like bottled water so I bring on my own. Provided for free at the lido buffet is coffee, tea, punch, lemonade, milk, juices etc. Coffee isn't the best on the ship and it s hit or miss whether I can drink it or not but they have a coffee shop like a generic Starbucks that you pay for which is better. They also have a sushi stand.
Cabins have 1 outlet for power so be sure to bring a multi-outlet plug or extension cord so you can plug in chargers, alarm clock, nite lite etc. Ginger pills works well for seasickness and doesn't make you sleep your cruise away like dramamine. A few people get seasick. Not a problem for us. Don't miss the dining room. Buffet food is just okay but the dining room food is fabulous. Be sure to order the bitter n blanc dessert. Order as much entrees, appetizers, desserts as you want. Bring a magnetized gift card or something that you can use for your in-room safe. Don't use your cabin card or credit card in case it demagnetizes it. I usually use a Walmart or Target gift card. Check your onboard charges (sail & sign card) daily on the tv in your room so you can make sure your charges are correct. Book ship excursions in advance if you plan to use them cuz some sell out before you get onboard such as swimming with dolphins. I swam with dolphins in Cabo and it was a once-in-a-lifetime experience. I booked my next cruise to take my kids on their first cruise and intend to have them swim with dolphins in Cabo. If you have an inside cabin, it is really dark all the time so be sure to bring a nitelite or you can turn on your tv to the bow camera and turn the sound off while you sleep then you will wake up when it starts getting light. Otherwise you will sleep your cruise away. Bring highlighters so you can mark which "must see" activities you want to do. I also bring post it notes so I can leave notes and instructions for my cabin steward. My first day, I always find my room steward and tip him a little extra and tell them to fill my ice bucket daily & anything else I need then I leave notes for them with smiley faces and "have an awesome day" messages to make them feel good. Sometimes I leave candy bars for them too. Read the capers daily to see what specials are offered. LIke they have internet specials etc.
Take your daughter to family karaoke if she likes to sing. Have fun!