First of all, congratulations for choosing that you want to spend your time envolved in such a worth-while sport. As a 14 year old myself, I feel that if more kids had dreams like yours, the world would be much better. Just have fun and be safe.
I am envolved in Western, so can't help you much on details. But, I've heard and studied some about steeplechase. Dangerous: very! Hard: very. Rewarding: un-comparable! Life with horses is dangerous - period! At our age, it aint like you're planning to hit Aintree tomorrow! I do agree that you need to be prepared, but if you have the want to do this sport, that will come. All you need to keep in mind is the safety of you and the horse.
My advice would be this:
~Find somebody who is worthy and can teach you and can help you along the way. They will be priceless after the flag comes down.
~Read everything you can get a hold of on the subject. Absorb like a sponge!
~Most of all, don't loose sight of your dreams!
Good luck and God Bless you!
P.S. Also, you would love the book "Blind Beauty" by K.M. Peyton.