First, the word “you” is ambiguous. Does the assignment call for a general discussion about the nature of personal beauty, or a discussion of your (the writer’s) own beauty. If the former, you might want to begin with a provocative hook statement, such as “Beauty is never in the eye of the beholder. It is generated from one’s own self-respect and vision of one’s place in the universe.”

If the latter, you might want to make a strong hook statement about your personal attitude toward your attractiveness to others, such as “When people try to compliment me, they direct their comments toward my physicality, not toward my inner self. While it is true that I am "bilaterally symmetrical," I want people to see the beauty of my attitude toward others, toward life, toward the universe.”  A speech on your own personal beauty (much the better topic) should immediately tell the audience that you are not going to speak about physical beauty (unless you are some kind of beauty queen and want to discuss your career as such).