That is likely the LEAST you will be expected to pay for college, unless you: 1) Pick a school with a lower Cost of Attendance, or 2) Get enough merit money to bring the COA below that.
Duke uses CSS PROFILE information to come up with their financial packages. They will likely include a student contribution in their calculations. If you your parents are divorced or there is a family business or primary home equity in the picture, the numbers could be quite different.