It is a good goal to aspire to academic success, but you will want to broaden that goal to include optimizing across all graded areas - military aptitude/performance, conduct, physical fitness, etc. The person who performs well in all those areas plus is respected as a good plebe who helps others and pulls their share of the team load, is the person who rises high in the overall order of merit (OOM). The OOM is multi-dimensional and determines who graduates at the top of the class and with distinction. Sure, if you went to MIT or an Ivy, the 4.0 academic goal is the only one in play. That well-rounded application you strove to submit and were clearly successful in doing? You have to be a well-rounded mid, as well.
You will also never have enough time to get everything done. Expert time management, efficient study skills, task prioritization and self-discipline will emerge as far more important as tools in your toolkit than arriving at I-Day brushed up on academics.
It would be absolutely okay for you to enjoy the rest of your college year with friends and family, focus on your physical fitness, and arrive at I-Day ready to execute Plebe Summer. The start of the academic year is a plunge in the cold deep end of a pool for everyone. If you have the skills mentioned above, you will be as well prepared as anyone.
If you are bound and determined to scale the heights of performance, there is of course recognition for those who stand highest in academic performance. But again - truly - it’s neither expected nor required to do academic work before you go. The start of the academic year is months away.