Personalized 3rd Birthday Mermaid 3 Year Old Girl Toddler Hoodie. Cute mermaid themed 3rd birthday outfit for a toddler girl with number 3 design. The Toddler Pullover Fleece Hoodie keeps little ones cozy and comfortable through all their adventures. Made with soft fleece and a smooth jersey-lined hood, it’s perfect for layering on chilly days. Ribbed cuffs and waistband help hold in warmth while side seam pockets add a touch of practicality for busy toddlers on the go.