Hi Alexander,
I replied to Liam so you will both be getting two posts.
One of the major things we have to deal with is how people perceive us. With Liam and yourself you wish to identify as male, fine. BTW as in the other thread have you discussed this with therapists? If not you both should ASAP.
Since you identify as male why should you correct anyone for using male pronouns? In fact you should be telling your teachers to use only male pronouns when addressing you. If you are unsure that is why you need a therapist to discuss things with. It is a big decision.
As for the class making fun of you, they may or may not. One way of dealing with this is to ask to address the class. Explain what TG is and the road you face. Ask for respect for a difficult time in life. Stand tall, look people in the eye and NEVER be ashamed.
I came out to my parents and family that I was female when I was 13, a long time ago. They could not accept it. I could. I have. The world has changed an awful lot since then. I hope that if I came out now at 13, I would have been given the hormones I so desperately needed before going through puberty.
Good luck Guys
Cindy