Actually if you believed the math that curvature is in proportion to mass, it would support your belief in dinosaurs at the center and the possibility of a hollow earth.
You apparently understand that in the center the forces are balanced. Being an equal distance from all sides this is correct.
You then think that as you move away from one side towards another, they remain balanced. This is incorrect as the forces are no longer in balance.
This situation is similar to the sphere within a sphere problem.
http://physics.bu.edu/~duffy/Physlab/EField/EField_Gauss_Text.html
Except the object inside (you) is not hollow and the lines of force connect to you, making your net charge non-zero.
The same with gravity. A hollow sphere with nothing inside would exert zero gravitational force on nothing. A solid mass inside would exert its own gravitational force to the outer shell. Equal unless moved from the central position.