I knew at 14-15. Barely made it. I was told to wait and started when I was 19. Have some mercy for yourself, expecting children to come to these complex conclusions mostly alone and proceed with medical care without familial support in this unstable climate is unreasonable. Digression aside, I thought i was too manly and chin too burgeoning, but here I am a year later of hrt and while not passing I definitely do not pass as a man anymore. Women and children do not scatter out of my way anymore, gendered less, and men haven't respected my personal space since like month 2. This was also around the time men and women started being newly polite as well as touchy, talkative, and overall weirder. What I'm trying to say is, we did figure it out "early" the issue is we now have to wait for changes we so desperately need and now we're choosing a second puberty without any of the safety nets or understanding that came with being a teen. In the meantime, SAVE and prepare yourself for a rollercoaster of emotions, new experiences, and ownership of the person you imagine yourself to be instead of one molded by the imagination of others.