You CAN prepare but don’t have to
If your course set reading before you attend then you SHOULD do that
If you want to refresh your knowledge of the subject by reviewing A level notes then you COULD do that
If you enjoy the subject, you may want to read independently but the books you choose and the subjects may not be a close match for any course modules but, hey, if you love the subject it’s all good right?
But no, you don’t have to prepare especially unless your uni asks you to