Hi Mariana,
I have an only child who is a daughter as well, and I am happy to share our experience in having her visit the
Children's Activity Centers at Walt Disney World. She has absolutely loved them! I remember having her spend and evening at
Sandcastle Club at Disney's Beach Club Resort when she was 4 years old, just like your daughter! She absolutely loved her time there. At all of the Children's Activity Clubs, we have found the activities and toys available to be exciting and fun for her. We have also always been impressed with the caring and attentiveness of the cast members working at the Children's Activity Centers.
That said, you know your daughter best. My daughter has always been outgoing and comfortable in social situations. At the time that we started taking her to the Children's Activity Centers, she was also in preschool and had experience staying at the child care center at our local gym, so she was used to being dropped off places with groups of children and other adults. You mentioned that your daughter can get nervous. If you think that going to a Children's Activity Center might be overwhelming for her, you can also check out
in-room babysitting at Walt Disney World. This is provided by the independent company Kid's Nite Out, which you can find online at kidsniteout.com. We have also used this service, and found that the babysitters that they sent were kind, and my daughter enjoyed that they would bring a bag of activities customized to her age and preferences!
Overall, we have had great experiences with both the Children's Activity Centers and in-room babysitting at Walt Disney World, but choose what you think is best for your daughter!