Your reasoning here doesn't make any sense to me. While it's true that God may know you're foolish enough to use this kind of reasoning to live with no effort and thus condemn you, it's also true that you could decide to live life with effort in order to please God. In that case, God would know in advance that you are not going to be condemned.
So god is not all knowing? He has created 2 options, do good and go to heaven, do bad and go to hell, but he dosent know which option you will choose? He just presumes you choose the Do Good option?
Why would you bring up some grade you might/might not have gotten? Why would that matter?