Personalized 1st Birthday 1 Year Old Outfit Adult Sweatshirt. Funny it's my 1st birthday design for boy or girl with birthday hat and stars. Stay warm and stylish with this classic adult sweatshirt, perfect for everyday comfort. Crafted from soft, durable fabric, it features a relaxed fit for added coziness. Whether you’re lounging at home, running errands, or enjoying outdoor activities, this versatile sweatshirt is a wardrobe essential for any season.