It took me 11 months to master the whole *** thingas waldszenen said, just practice AS SLOW AS POSSIBLE and repeat every bar even teh simple ones, and do not leave anything for later. if there is some bar which is uber hard, keep practicing it slowly and gradually build up speed until you master it then move on. Good luck, keep us informed about your progress.
was your great grand-dad Wilhelm Kempff, by any chance?
How I wish...... Nope, my great grand dad was just some lucky guy who was good at piano and got to have masterclasses for like 6 months with Cortot.