Being good at one or ten sports doesn't imply leadership, but the Academies like them because they have sports teams to fill, and they hope one learned how to take wins and losses gracefully, how to work with others towards a common goal, and because sports participation and achievements show signs that the participants have been able to focus themselves on improvement over a period of time. NJROTC + Girl Scouts + 3.8 GPA + being good at sports should make you competitive against other women/men. (1 in 2 competitive, qualified candidates are appointed.)
The only problem I can see (and if I'm being very critical, I apologize) is that your definition of leadership is "I play a lot of sports and am tops in the school." From what I have heard, one common problem with "student leaders" is that they have no idea what leadership is. It is my opinion that the Academies would like to see a firmer grasp of leadership in their candidates. At least in my college, one of the other "student leaders" was asked, "What makes you a student leader?" The answer given was: "Because I do very well on math tests."
Instead of telling the Academies that you are a "leader" because you are "one of the best in your activities", you should seek out and show true involvements in leadership, such as leading others towards a common positive goal. Highlight whatever you have now, and add to it over the coming year.
Your qualifications are very important for the school aspect of the USNA, but for the military-managerial aspect, you need to show Officer potential by actually leading and inspiring groups and creating new and wonderful things in your community. The thing with high school is, one person can get a lot of "leadership positions" by having a good GPA and being liked by others. That does not make him or her a leader in the sense of the word that the military looks for.
If I was an Admissions Officer right now, I would try to hint that you have shown absolutely zero leadership ability, and would deduce that the reason for this is because you have zero interest in leading/managing people on a boat, and that all you will want is to fly, nothing else, thus showing little Officer ability.
Now, I have ruined the outcome by telling you how Admissions will think of you

Hopefully, you will not use this information only to highlight leadership roles to increase your chances above other candides like you who have no idea what leadership is but who just want to fly; no, hopefully, you will actually learn to love leadership and take on leadership roles that will actually make you a true leader!
Lead some Clubs, etc. Take initiative. Find miscommunication and try to solve it. Etc. DON'T STRESS YOURSELF OR HURT YOUR GRADES. But, keep in mind what I said

It doesn't matter if you are selected XO/CO or not, one can be a leader in any situation. Nor does being selected XO/CO make you more of a leader, if you were to be promoted because of good grades and nothing else.
You don't want to be selected XO/CO simply because you are the best candidate for the job of the group which you're in. (The hardest working, the smartest, tallest, fastest, etc.) At least I would not be. Instead, I would want to be selected XO/CO because of being recognized of being an awesome leader, interested in the well-being of my team. Therefore, the Academy will find your actions more important to your titles. To get that XO/CO and have opportunity to use leadership skills...just start using leadership skills now and you will be noticed! And figure your flying will be 2nd to being an Officer, where you will be responsible for thousands of people!
If this still sounds exciting, definitely join the Navy!
~ Helping People See Better, One Hour-Long Post at a Time. (TM)