Erina,
Welcome to the site. I agree with Erina, it is a slow process. So is transition. I know that is disappointing to here when you feel so badly about your body. However, it is long distance, not a sprint.
Are your parents aware and helpful? They might be your strongest advocates and way to move toward this goal. If they are supportive but need information, you might encourage them to join and go to our significant others part of the site. They can potentially talk to other parents experiencing this with their children.
The first step is usually therapy. Whether starting with a school counselor to point you there or finding out if there is a gender therapist near you and scheduling an appointment. Most surgeons will not operate on a minor. Others might but they would need full agreement from your parents. Surgery usually requires two letters from medical and psych professionals, suggesting this is right path for you.
If your parents are accepting and you were okayed by a therapist, you might be able to start Hormone Therapy. Usually they will not give estrogen to start for a teen but begin antiandrogens. That would knock down your testosterone levels. Many MTF's find that just starting with that helps a great deal with their dysphoria(discomfort). Once again, minors need their parents to okay this. Often the enodcrinologists(Dr.s who deal with hormones) require a letter from a therapist saying you are ready to start.
There is a section here for under 18 y/os called youth talk. You might find others going through similar things.
Not sure if this helps.
I also want to share some links with you. They are mostly welcome information and the rules that govern the site. If you have not had a chance to look through them, please take a moment:
Things that you should read
Once again, welcome to Susan's. Look around, ask questions and join in.
With warmth,
Joanna