First time posting something. So I will start like this- I am still in high school. I have told people about my future plans to transition.
To get a sex change. I am going to be graduating next year. I don't know where to start, I have anxiety! 

Think you're already started.

One step at a time.

And before I forget, Big Welcome to you.

Agreed if you have told people, you are already on your way.It's a good sign that you have accepted this already and are able to communicate it.

The anxiety does lessen ( I 'm not sure it ever fully goes away) as you become more comfortable just being who you are. 99% of acceptance, comes fom within you and i self acceptance. Once you can do that, the stress melts away.Welcome.

Seana

Thanks, it's great to be able to talk about these things to people other than my therapist. 

Hey Girl,

Just ask question and you should get plenty of good advice around here. So, yeah, happy transition

OO

Welcome and good luck.

Therapy, therapy and therapy! nearly all therapists work on a sliding scale, if you are still so young and do not have much money, I am sure a good gender therapist will not turn you down, and will charge a minimal affordable fee.
I mention Gender Specialist, because this is very important and a crucial point. Non Gender Specialist can in fact make more damage without proper understanding and clear direction of where to go with it.

Love, Inna