I have taught at the high school level for over two decades. From my experience, it is not too late to pull up your GPA and prove you have what it takes. I have seen plenty of students pull their GPA up and improve their class ranking with diligence. We have learned through our DS's experience that there are many factors in the process of earning an appointment, and you will need a master plan to manage the journey.
The first thing you need to do is change your perspective. Right now you have a challenge. Be brave and choose the path that speaks to your heart because no matter how much support you have, at some point you must take steps on that path on your own.
Secondly, take charge of your journey. Meet with your Guidance Counselor before the end of the school year and make a plan for the remaining three years of high school. Keep the academic plan a little flexible, but take the most challenging courses available to you. Keep the parental units in the loop. Learn everything you can about the SAs as well as VMI and try to make contacts with cadets and graduates. This forum is a great place to start. It is not too early to think about visiting VMI or the SAs if it is feasible. Find out when your Congressman is hosting his/her Academy Days and make the time to go to every one. Do not neglect athletics and leadership opportunities.
This seems like a big "to do list", but you have a little bit of time to craft your list and make the necessary changes starting now. Just remember to look at the list as a series of small steps on the path so it is not too much.
Do not forget to carve out space on your list for a Plan B, C, D , and so forth. Above all else, you need to be ready to risk failure in your first attempt. That is why courage is so important. Thousands of applications are started every year, but many are not completed for various reasons. You will not know if you can unless you try. There is the very real possibility that you will not achieve your goal in the first attempt. Are you willing to find an alternate path to commissioning? Will you go through the process again to pursue your goal?
I realize that thinking about all that you need to manage is a bit overwhelming. It has been for my DS off and on since he decided he wanted an appointment four years ago. He did not succeed in gaining an appointment this year which was a bitter pill to swallow after the time and energy he put into it. But, an amazing and unexpected opportunity presented itself. His Plan B continues to grow in leaps for him. And, he has already started the "to do list" to reapply for the Class of 2022.
The worst that will happen if you apply is the dreaded TWE. But, you will have plans in place to get you through that. On the other hand, you could very well end up with the BFE so many dream about. At the end of the day, it is up to you.