I hate to be the one to disappoint you, but I think it is pretty important.
Back when I was a teenager I badly wanted to be an RAF pilot. I got talking to an RAF recruiting sergeant at one of those tents they have at air shows and I told him what I wanted to do when I was old enough to join... His reply was "Well, I hope you have perfect eyesight" and he gave me a metal badge of a Spitfire, which I still have. It devastated me because I'd just recently been diagnosed with a form of colour blindness.
I dunno how old you are, but I'm guessing you're fairly young... I was only about 13 at the time. Ambitions and interests change and evolve a lot when you're growing up, and what seemed like a crushing blow at the time, I now see in a positive light. My personal interests soon shifted to music and I got heavily into the guitar, grew my hair long and formed several bands... A million miles away from where I thought I'd end up. But I wouldn't change that now for the world.
Basically, I'm saying don't see it as the end of the world if you can't follow one particular dream. Keep an open mind, look around and chances are there is some other career path that will inspire you just as much if not more if you find that particular one is closed off.