Mine was a size 0 too, 25 years ago and it had to be taken in.  I don't know if they had vanity sizing back then, but I remember that there were a lot of butt hurt feelings from the salespeople about how I needed to gain weight to look good in it, that I was a bag of bones.  How many people have you ever heard say they were told they needed to gain weight for their wedding dress??  Crabs in a bucket..