Thank you for all your suggestions. My father isn't usually overbearing like this. He has never came down so hard on something so unreasonable before. But I am a stubborn person, and I think I may choose to wear it curly, but not really because I like it curly but for the principle of the matter. To say that I am no longer a little kid and while you still have much control over my life, I have to have control over something, and my body is mine and what I do with it is my own choice.
Is this a bad idea? I'm really not sure how to handle this like a mature coherent person and not come across as a spiteful rebellious teenager who doesn't know how to pick her own battles.