I definitely think sizes are running waaaaay bigger than when I was a teen (30 years ago yikes lol). I think it's because so many people are overweight now and sizes have to be made bigger, and the industry knows us gals, WE DON'T LIKE TO BUY BIGGER SIZES LOL.
Today for instance, I'm wearing a size 8 slack style capris and size 10 jacket right now at 158.8 and I wore these sizes at 140 twenty years ago. I am a big boned and carry my weight really well, but still...just my thoughts.