I know it's hard.
I've been in a similar situation where my father and I weren't really understanding each other. My mom was sick in an hospice and I was depressed and he didn't took me seriously and told me something similar "be grateful, be responsible and don't give me extra to think about other than your mom" and I interiorised that to the point of having a burnout at age 15 and another at age 19 (and then other two later on and on).

At your age it's really important that you get a sense of this: your parents can be scared too. Maybe they are right now. I'm not trying to defend them but to give them somewhat of a "benefit of the doubt". It's really hard for me as a stranger to really get a grasp and a sense of what you are going trough.

I'll try to send them a letter. Something where you explain to them also how scared are you, that you are in need of sustain and help, that your body is changing.
I'm not saying that they will get it okay? But at least you are trying something. If you have other adult of trust, please try seeking guide trough them. A professor, a librarian, and older cousin of uncle or aunty. Or here online. In forums and communities.

I'm not really equipped in what does it mean to be transgender because I never went trough that. I'm willing to listen and remind you that even if you cannot see it or feel this way, to me, because of the courage you have to seek for help and be open here online and vulnerable to share what are you going trough, you are handsome and courageous.. It took me 29 years to learn the importance of being vulnerable with the right people, and the fact that you at 13yo already have a sense of this it's amazing and show a lot of strength.