You do get to set your boundaries on what you will and will not share with your T. This is actually an important thing to learn in therapy--how to set boundaries. If it is just too personal and private to bring in the scale, it is OK to set that boundary and tell your T about it. Perhaps she will even be proud you are able to set a boundary. If you become more comfortable and feel less private about this at some point in the future, you can always bring in the scale at a later date. Good luck.