We took our daughters 5 years ago when they were 4 & 7 and they had an amazing time! We brought coloring books, little art projects and small games to fill the time while under sail. They also brought their dolls who had swimsuits and a life jacket just like they did. For the most part the kids spent the time looking for turtles and other animals while we sailed and were never bored. We’ll be there again in 2 days with our now 9 & 12 year olds and our friends who have a 9 & 4 year old. As long as your daughter knows how to swim I say go for it! I love to hear of people traveling with their kids, it’s definitely not the norm where I live.