Not the same at all - DS is in 00 clothes and has size 2 feet, to go by his socks. Even at 5 weeks old he was too big for 00 shoes!

Due to foot development, please consider using bootees, not shoes, for outdoor play. Too rigid a structure on the foot, and certainly too tight a structure, will permanently damage the bones in the feet (take it from one who has been there and had the corrective surgery).