Alexis, this is good but it can be better. Cut out the part where you say that growing up you thought you were average. Use the portion where you say that you realized that you were unique as you matured. Use the remaining characters to describe why you realized you were unique in the best way that you can. For example say "Growing up, I began to realize I was unique because I could do back flips when others could not." That is only an example, I did not mean to trivialize your uniqueness. I just wanted to give you an idea as to how to approach the statement within 140 characters :-) It is possible to give a complete description of yourself using the correct terms and within 140 characters.
