How do I define myself?

My identity. Who am I? I've been asked this question before, in english class, and outside of the classroom, and I have always found it very difficult to find an answer. What defines me? is it my looks? or is it what I do? or maybe it's how I act? These are the questions I ask myself trying to figure out who I am. At this point, I believe i have not defined myself yet, being only 16 I have barely lived a quarter of my life and I have so many new experiences ahead of me. So not only have I not identified myself yet, I believe that my identity will continue to change the older I grow and the new things that I may experience. Although at this moment I may define myself by the sports that I do, or the clothes that I wear, or the group of friends that I surround myself with. But what about in 20 years? There is no way of knowing if any of these will stay the same. Because of this, I believe that putting a label on myself, or defining my identity is unneeded, because there is no guarantee that i will be the same person today, that i will be in a week, month or a year. I believe identity is constantly changing and it all depends on life experiences and growth.