Personalized Half Marathon My 1st 13.1 Run Toddler Long Sleeve T-Shirt. Cute half marathon running Toddler Long Sleeve Tee - Charcoal outfit says my 1st 13.1 run for girls. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.