Ahoy there, Jon. Multi-generational trips on Disney Cruise Line are a great way to make magical memories together. Make sure to take lots of pictures!
All 
U.S. citizens, regardless of age, on a closed-loop cruise (meaning it begins and ends at the same U.S. port) need an original valid U.S. passport, original valid U.S. passport card, or a state-issued original birth certificate. If you or your daughter uses your original birth certificate, you will also need your physical government-issued photo ID because you are at least 16 years of age. Digital/mobile state-issued IDs are not acceptable for sailing. 
The 
Disney Magic was the first Disney Cruise Line ship I sailed on, and I had a toddler myself. He loved the 
character experiences where he got to give his favorite Disney characters a hug and take a picture with them. On the day of the deck party, I made sure he got a nap so he could stay up a little later than usual to party on the deck. The 
Disney Cruise Line Navigator app will have the activities listed once you embark on the Magic. This will help you and your daughter plan each day's adventure for your family.
Jon, if you have any other questions, come back to visit us at 
planDisney. We would love to help you prepare for your Caribbean vacation.
Adventure is out there!
JoVonn