There has been tons of great gouge, but I can't emphasize varsity sports enough. I did MCJROTC and everything that came with it drill team, color guard etc. When the time for a Navy scholarship came I didn't get one. Varsity sports help alot. I earned a ROTC scholarship once at Tulane due to my grades and my technical major. Tech majors will make getting a scholarship on the Navy side much easier. My brother is in the same position I was and he also focused solely on JROTC.
Also, JROTC does brainwash you. I felt like I had to go Marine Corps for the longest time, then the lightbulb went on, and I decided I had to FLY Navy!
Your motivation, drive, and determination for someone your age is extremely impressive. Keep it up, never lose sight of your dreams, and you will go far.