We have sat in on a couple of academy admission meetings..definitely begin the application process early! And if serious, find some leadership opportunities for your young people--according to our Congressman's assistant, the main disadvantage homeschoolers have is in the area of leadership -they strongly value leadership in sports, band, student council etc. One of our friends (a non homeschooler) was accepted to the Naval Academy and his application process took 3 years-he started his Soph year of high school. Another option is the ROTC program-they also like leadership but less stringent-LOL, can you tell we are military focused...also check for a local Sea Cadet program if your area has one. This is a high school program that is sponsored by the Navy League and although has no military requirements post high school-gives exposure to the military "way" to teens and also if they do decide military is what they want to do-will earn them higher rank in the Navy, Marines and Coast Guard after boot camp.
Our local homeschool resource center has a college fair and two(? maybe 3) military academies send representatives. The Naval Academy even has a page on their admissions info that addresses homeschoolers. (It is my oldest son's #1 college choice.)
We have a couple families here who are wanting to get their child in the military and this was very helpful. One family just wanted to enlist their son, and the Army is giving mom a very hard time about it. He is requiring a certified transcript and all sorts of stuff HSLDA said they don't have to have.