Chances for USNA or NROTC

<p>Hi,
I am a Sophomore and I am wondering what my chances are and what is recommended to have to get into the US Naval Academy or NROTC at a civillian college. I am also considering the University of Pennsylvania so I would also like to know what my chances are for that too.
I go to a very large HS. I got 4.0 in my Freshman year and 4.57 in Sophomore. I have not taken the PSAT, ACT, SAT, or SATII's yet. My extracurriculars are mission trips to Mexico every year during Christmas week for one week to do labor work and to help the orphans there in Tijuana. I am also a pianist for many years and have done Certificate of Merit for Piano level 8 with Branch and Convention honors. I have also taken college summer classes for business and another one for law. I know that my extra-curriculars are pretty bad. I think I am relatively fit and could pass the physical exam and test. My questions are what are my chances are to get in? If it matters if I do a sport or not as long as I pass the fitness test? When to and when to apply? and suggestions for future EC activities.
Thanks</p>