Personalized 4th Birthday Mermaid 4 Year Old Toddler Hoodie. This cute mermaid themed number 4 is just right for a little girl celebrating her 4th birthday party. 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.