Ahoy Cristine!
Welcome to the Moms Panel! I'm also looking forward to a sailing on the Disney Magic and can't wait to see all the new enhancements when my family is aboard in a couple of weeks!
I'm glad you asked this question because when my family began cruising my active son was just a few months younger than your daughter so I completely understand wanting to keep your princess busy while onboard! First, I definitely recommend reserving some hours (a nominal hourly fee does apply) at the newly redesigned;
It's A Small World Nursery! This space is bright, interactive and offers crafts, games, story time, and movie time! It is stocked with age-appropriate toys, and the childcare providers are wonderful. Also, you will want to check your daily cruise newsletter, the Personal Navigator, for toddler activities planned by the cruise staff. These activities are usually scheduled during the morning hours and often involve Disney Junior so they are just perfect for all the young sailors onboard. Listed in the Personal Navigator, you will find Open House hours for the Oceaneer Club and Lab as well. During these scheduled times you can take your daughter to explore the innovative spaces to play and/or participate in the planned programming. If she enjoys getting wet, she will love splashing around in Nephew's Splash Zone! This area is just for those cruisers three and under so I know she'll have a blast!
Also, be on the look out for family dance parties, deck parties, and special holiday events too!
I hope my answer is helpful, Cristine! Please let me know if you have any additional questions!
Have a magical day!
Nancy