A good prerequisite for studying chaos is a class in ordinary differential equations (ODE), which is normally taken after learning about integration in Calculus. With this background you can start learning about the Lorenz Equations.
The next class to take after ODE is Real Analysis, since chaos is all about analyzing sets of real numbers. This background will get you ready to learn about the various kinds of fractal dimensions.
I recommend this course of study instead of a popularization book.
Edit:
The book I suggest for learning ODE is 'Mathematical Methods of Physics' by Mary Boas.
The book I suggest for learning Real Analysis is 'Principles of Mathematical Analysis' by Walter Rudin.
The books I suggest for learning Chaos Theory are 'Nonlinear Dynamics' by Steven Strogatz followed by 'Chaos in Dynamical Systems' by Edward Ott.