It's (almost) never too late. You still have 3+ semesters until USNA considers your application. Plenty of time to bring up your GPA. An upward trend is a good thing.
Also, remember that your GPA is just one factor in the academic review. Much depends on the classes you take, whether you (eventually) take APs, your class rank, your SAT/ACT scores, etc.
You can't change the past. You can improve in the future.