A VBB baby is more greenish as a baby.
https://78.media.tumblr.com/be470fbf...ribzo2_500.jpg
Then they color transition as an adult.
https://ball-pythons.net/forums/cach...bluebeauty.jpg
Either way your animal is great looking and should make a fun pet.
Does she shake her tail when she is trying to get you to leave her alone. Is so cool to see the rattle snake impression for sure.
EDIT: I apologize. You said was a Japanese rat snake blue kind.
https://i.ytimg.com/vi/3Uj9Rn2CfzM/maxresdefault.jpg