Ya I think you should. I mean like, why not? People obviously don't understand what a special occasion is. I'm thirteen as well and I, along with all my female classmates, wear heels to special occasions.
Uhm I'm 15 and I wear 6 inch heels. I don't see how that would cause people to look at you different or anything? I started wearing heels in like 5th grade! Haha (: you learn to walk in them and now I wear heels everyday to school (:
Wearing high heel shoes will actually cause problems with your feet such as hammer toes, calluses. I wire heels a lot when I was younger until I realized my feet were starting to look Luke my grandmothers. There are a lot if practical shoes these days that look nice and have some heel.