If you have D boobs or bigger without implants, have some junk in the trunk but still have a clearly defined waist, and can wear reasonably tight clothing without the dreaded muffin top rolling over or back fat behind your bra strap, you are curvy.
Anything larger is BBW (or more) in my book.
Sizes of women's clothing are being inflated to make chicks feel better. Size 6 today was probably size 10/12 a few years ago.
All that being said, it is all a matter of preference so ladies, please just put accurate height and weight in ads and let us decide what we like.