This book assumes that you have no programming skills at all, but are willing to learn. You should also have the ability to think in abstractions.
You should realize that learning how to program might take a significant time investment. It does not suffice to just read the material and do the occasional small exercises. You will have to practice with the material and also do larger exercises, if you really want to gain the ability to create programs. If you stick to the basic chapters (everything up to dealing with text files), if you have no programming knowledge at all, you should count on having to invest between 100 and 200 hours to get to the finish, depending on aptitude. Learning everything that the book has to offer will take between 200 and 400 hours.
Note that this book will not try to teach you to be a professional programmer. It teaches the initial skills that any professional programmer also acquired during his or her education. After teaching those initial skills, the book ends. For most people, this is enough to deal with programming tasks they encounter, and provides a sufficient basis to learn more if there is a need.