Tips on to have a smaller baby?

Im due in December but i dont want a 9 pound baby! I want a 7 pound baby, just a perfect healthy weight. People say exercise help but it depends on the baby and what you eat doesnt matter. If there any way to keep her smaller? Im not even that big yet ive gained 35 pounds but i dont look huge but i have a round belly. I have 11 weeks left. Any advice??