Here is the final word according to the OCR (Officer Candidate Regulations...you will learn to live by these). All female IC's (indoctrination candidates) are required to have their hair cut to no more than 2 inches. After the indoctrination phase, OC's are allowed to grow their hair out according to Navy regs. That said, some Drill Instrustors interpret the "off the face and collar" to mean that your hair can't fall in your face, and they require their females to get their hair cut every two weeks (you can't wear pins or anything in your hair until you became Candidate Officer). Some don't. Sometimes it depends on your hair. So basically its just the luck of the draw if you can start to grow out your hair at OCS. I was lucky and only cut it once after the intial cut (and that cut was on liberty to "fix" my hair).
All of that said, hair is hair and the cool thing about it is that it grows back and you don't have to do anything to get it to grow back. It sucks, yes, but after your first Wednesday at OCS, you will be glad to not have hair to mess with. I had long hair (to my elbows) before I went to OCS. I cut it to my chin and donated before I went to OCS. You get used to short hair quickly and to me, its a very small price to pay for the goal you are attaining.
EngineGirl