Personalized 100 Days Of School 100 Days of Cool Infant Dress. This Happy 100 days of school design is the perfect outfit for kids looking to celebrate their 100th day of school in style. With its cute design, it is sure to make your little one stand out. Whether it's for a boy or a girl, this outfit is a great choice. Your little one will be adorable and comfortable in this 100% combed ringspun cotton 1x1 baby rib dress!