Congrats on your new little one.
Is your girl's barking mean like or friendly-wanting to play barking? She could just be showing your little one who is the alpha. Your little one will have to either learn his place or establish himself with your female.
Given that he's a baby yet, I would keep an eye on them just in case but I think that your little girl is just testing the waters and wants to make sure that he knows she's the queen of the castle. Before you know it, they will be best of buds.