If u think School will change urs grade then u r in big fault .look other students how they get the good grade even top the school that u mentioned .

work hard .work according to time table at home .and aske question again and again untill u understand the topic .did u aske questins from urs teachers of different subjects when u didn,t pick the topic or urs teacher didnt responce u .i think urs answer ll be NO .so look at urself dont blame school

cheers and start urs new life with thrilles and actions and working hard .u ll success 100%