Depends on what you want to do with life. Do you plan on going to college? If yes, you probably do need to cram. If no, I wouldn’t worry about it. I was a bright kid growing up, but college never really interested me as the way to go. So I slacked off and didn’t worry about tests or grades or any of that stuff. Instead, I focused on learning skills and working at my high school job. I got more out of doing those two things than I ever did from high school. I got the skill sets to work on machines which I use everyday at my current job and I saved up money to help me get a step up in life. Of course, every person’s path is different and you need to do what feels right for you.