Sewing a Dress Today

This morning I'm ready to work on Butterick B5100, view C.  I have a feeling I'm going to have to make it a little bigger or maybe a lot bigger. It's a sheath dress and I don't want it to be too tight. And I need to layer things over and under it. Remember, more than likely you cannot sew any pattern straight out of the envelope and have it fit you.  You will always need to make some changes in arm length or where the darts point or how short the waist is or something.  I read in an alterations book only 6% of women can fit into a pattern made straight out of the envelope. So take the extra time to measure yourself and compare it to the pattern specs.