Reducing width of bodice

My daughter approximately fits the size 12 building block dress. I made a muslin and it is a bit baggy on the sides. I gradually tapered the bodice starting at the arm hole down to the bottom of the side where it is taken in 1/2 inch. Is that an acceptable alteration? I am planning on reducing width of skirt by 1/2 inch as well so the bodice and skirt won’t be off.