These are size guides- items can have a small variance depending on style and preferred fit. We do our very best to insure that items are sized correctly. If we feel that sizing on a specific item is inaccurate, we will make a note in the description.
If you have any questions, please contact us anytime! We'll be happy to assist you. You can email us anytime at customercare@marienicoleclothing.com! If you'd like to join our VIP Facebook group, you can see even more real life customer photos. 
Girl model is 8 years old and 70 pounds. She is wearing a size 8Y. 
Boy model is 6 years old, 47 inches tall, and 52.5 pounds. He is wearing a 5Y.