How to convince my feudalistic mom and dad to let me color my hair

Why not talk to mom and dad and assume that they will disagree? Reasonable explanation is necessary, but not to use excessive ways and means, then not only they will not agree, and will make them more resentful. People have the right to pursue beauty, I think the appropriate use is not excessive, but to grasp the scale, at the same time you can propose by your mother to accompany you, in the process of dyeing your hair, you can let your mother to give you a little bit of advice, so that not only respect for their purpose, your purpose has been achieved. In addition, you said you are a student, but did not say you are reading a few years of students, if you are still junior high school students, that really do not agree with you to dye your hair, all chemicals, you are in the stage of growing body, on the health of the unfavorable.