Many people have had the same problem, personally I found Air Law incredibly dull and I'm not the only one. Your flying school might well do a ground school where an instructor can work it through with you. A working environment with others around may suit you more than just reading a book and taking notes.
Little and often may also help more than attempting to do as much as you can as quickly as possible. Take it a chapter at a time, do the questions and see how you get on. Once you're happy with the Pooleys book, hit the confuser (it IS good) - those questions best resemble the actual exams in style.
Take your time over the whole process, don't be "hurried" into going solo, as much as you may want to. At 16 you probably have GCSEs coming up which are quite a bit more important than flying stuff (as much as you may not want to believe it!). I was in the same situation as you once, so I appreciate that something like Air Law may seem a bit alien at first. If you continue to have problems then talk to your instructor, it is their job to help you through the process and give you advice.