How did he go to college?
It has been a long while since I have seen "An Officer and a Gentleman" but from what I remember his dad was kind of a bum and did not particularly like him so it is doubtful his dad paid for him to go to college. The character was also a rebel, troublemaker, and a loner which means he most likely did not do well in school to get a scholarship nor did he likely do well in college if he was such a rebel and misfit.
The character did not really seem like a college graduate to me from what I remember in the beginning of the movie which had me thinking was it clear he was a college graduate in the movie. He would have to be a college graduate in order to be able to be a officer candidate at his age unless he was supposed to have been enlisted in the navy for several years which would not have been the case with how he acted and him having to shave his head in the beginning.
I thought it was odd and not very believable for a rebel troublemaker rougher character like Gere played to also have been a college graduate and going on to be a officer candidate. It would have been more believable and realistic for the rebel loner character not to have gone to college and enlisting in the navy or else they should have written the character as a little more clean cut and less of a rebel in order for it to be believable that he was a college graduate and he would qualify to be a officer candidate in the navy.