The whole groundschool aspect starts to make much more sense after your first 5 hours, or so, in the air. So don't overwork now by reading all those volumes of AFE books before you go to OBE because you'll soon realise it was a waste of time. You have no frame of reference prior to airwork unless you've alread done some significant flying time therefore I;d advise you save your brain batteries for when you get out to the USA.
VFE.