Popflex Babydoll dress

Hello! Been trying a few things with Popflex the last couple of months and recently got a black babydoll dress. I tend to be a medium in tops and size 10/30/L in bottoms. I’ve only tried the cloud shrug (m) and long sleeve corset top (m), and I decided to go with a large for the dress.

It’s super comfy and so cute! But since I have a small chest, there is some gaping if I move my arms close to my chest or bend over. The rest of the fit is very comfy and I’m worried a M would be a little too tight….should I bother going a size smaller?