Burberry infant bodysuit dress size 1 month

Burberry bodysuit onesie dress for infant. Dress says it is size 1 month, in the included pics are my baby wearing it at one month but she was small. At that point maybe 7 or 8 pounds at most and it was still big on her. If the bodysuit doesn’t fit, I was told by salesperson there is also option to wear it as a loose fitting top and not snapping the onesie buttons. My baby wore it once for Christmas during covid then didn’t have a reason to get dressed up again. Like new.