Speaking from my regrets these past two years, learn as much you can in the summer holidays (i assume u are in year 11 or sth) before dr du teaches the stuff. like, learn the whole syllabus or as much as possible (trust me, it is absolutely possible) and you will have more fun. I nearly lost all my interest in doing mathematics because that place is like a factory once you enrol in their extension 2 and 1 courses. They spoonfeed you so fast in a1 and most of the kids there have alreay done accelerated ext 1 or adv so they don't seem to blink an eye when james du whizes through. learn it yourself before dr du does it. their value is in their questions and the zoom homework help 8 hours on the weekend support live.
It is not a good way to learn.