Slippers run small. My daughter just went to a size 10 and her toes are at the very end of a size 9/10. However, they are so soft that I ordered a size larger. Your younger cousin runs one size smaller.
Scurtain Toddler Slippers Artificial Non Slip Boys' Shoes for Slippers
55 Review
π IEvolve Navy Blue Dinosaur Boys' Prewalker Moccasins Shoes - Ideal for Slippers
50 Review
π Yalion Slip-On Leather Crawling Shoes for Toddler Boys
66 Review
COSANKIM Slipper Sneaker Moccasins for Toddler Boys' - Shoes in Slippers
48 Review
Quick-Dry Closed-Toe Water Shoes For Boys & Girls - Ideal For Aquatic Sports - Toddlers & Kids Size - HOBIBEAR
51 Review
π Highly Durable Kids Running Shoes - WETIKE Boys Basketball Shoes Non-Slip Outdoor Trainers for Girls (Little Kid/Big Kid)
8 Review
π Jordan Youth Air 5 Retro GS 440888 600 Raging Bull 2021 - Size: Unleash Sneaker Style!
5 Review
HOBIBEAR Lightweight Athletic Sneakers For Kids - Perfect For Running, Walking, And Sports!
10 Review