What should I major in or double major in?

I will be going to the 9th grade next year. My long term goal is to join a government agency like the FBI, CIA, and NSA. To be in the FBI you need to have 3 years of prior experience (military or police officer). I just want to know if I should join the military? Which branch of the military has good intel officers or has the most intel positions? Which type of degree would help me the most to get into any of these government agencies?