You be you. As for people who might make assumptions about your gender, just ignore. They will figure it out, or not. Voice, face structure, body shape, body language, all contribute. Your voice, how you express yourself, your actions, your eye contact, your command presence, will weigh far more than hair length in the military.
Repeat as needed to yourself, “I am a woman, therefore everything I do is feminine, and I get to choose how I express that.” I spent twenty-six years in the Navy, had braids, buns, short, long. It was whatever I felt I had time for and could keep looking good.
I have known many women in the military with very curly hair, thick hair, thick and curly hair, who had short, easy care pixie cuts. Saves a whole lot of time. You’ll have plenty of upperclass women to observe and learn from.
Have some fun googling “military women short haircuts” and “military women pixie cuts.”
You’ll be too busy thinking about other things and too exhausted to do more than basics until you hit your stride and figure the place out, and you’re in fine company. The more senior you get, the more you will be able to carve out your “look.”
I’ve promised myself to go full pixie when I hit 85 or so and don’t want to do much more than run a finger through my hair. Here’s my target look, the late great actress Jessica Tandy in her late 80’s. No problem mistaking her for a man. In the meantime, check out Charlize Theron. I would bet there are no male cadets who will have that haircut. Of course, you wouldn’t be doing that much make-up in uniform, but that leaves potential for if and when you want to when you have civilian clothes privileges or are in formal dress.
To recap, you be you.