If you can write a letter that is clear and effective, age is nothing. You don't need to say, "Hi, my name is Agwoeiaja Dieowijwf. I'm not old enough to vote, but I think my position on this matter is important!" if you write a letter. A letter from a concerned citizen is a letter from a concerned citizen. I wish someone had the balls to tell me to write a letter to my reps when I was 15. It would have kept me from half-supporting issues. I don't write long, hand-written letters in legible font unless I really mean what I say, so it would have pressured me to research issues, and go to greater lengths to become involved and passionate about issues like where our military efforts and tax dollars go.