Baby names

Hi! My 1st time posting on here so bare with me please. I would like to get the opinions of all of you about a situation I'm going trough. I just found out that my EX-husband is naming his new baby girl Charlie. I KNOW I don't have any place in saying what he should name his baby BUT this is my problem with it. We named OUR son Charles Jr., "CJ" is what he goes by. Technically he's Charles IV. He's proud to be a junior and named after his dad. So I told my EX that he should really think it over because I fee like he's taking something away from our son. Yes, my son is too young right now to see what I'm trying to get at and maybe he will never care. But I feel it's my duty as his mom to protect him. Even if it's not a serious matter now I feel like someday he's going to realize that it's not cool and I don't want him to gel hurt. Am I over reacting? Does anyone see where I'm coming from? Thanks!