Basicaly i was so hooked by other things (girls, guitar playing, hockey...) that i did not realize i only did the minimum to get through my classes and i thought that every subject was worth. Thus, even if i knew i liked history, i failed to understand that thos was my real interest. This led me to choose biology at the University, after three years i quitted and switched to history, where i'm still bogged down (not easy to study, have a family and work, anyway) So let me give you this counseil to you: stick to what interests you as much as you can...