In addition to getting payments going back to your application date, you can get up to 12 months of retroactive payments for the year prior to your application date (or your protective filing date, discussed below) -- if you were disabled that long ago.
Characters will receive one specialization point at level 7 and another at level 14. Specialization points can be saved for later levels or used mid-level (the Level Up button on the stats sheet will be active if there are unspent specialization points).
Source: The Role of Education in the Military Promotion Process, RAND Corporation. As a Specialist (E4), you can earn up to 75 points for civilian education, or nearly 10 percent of the possible 800 Army promotion points. For a Sergeant (E5), you can earn up to 100 points, or 12.5 percent of the total possible.