I dont konw whether i am lazy...

I am writing a bool,whose words has passed one hundred thousand..now i am still inist on writing..i like it..

However,My major subject's grade is worse. Since some class is not my like..so I did spend very very little time on it..As a result, My score of that class was low..

I am a little confused..Am I lazy?? Should i sacrifice the hobby's time on studying..In my opinion, i agree..but I dont want to do...