Criticising anyone for their appearance is unforgivable.
There is never any justification for commenting about people's hair, make-up choices or dress. Ditto speculation or judgemental comments about their scars, facial hair, genitals or breasts.
I hope you can reconcile with your child. My son is trans, and when he came out I had no real idea what that meant. Being very gender non-conforming myself, I thought I did - but that wasn't so.
When we go out, he will often be wearing a skirt & make-up and have his hair beautifully done. To say the least, I will not - he shaved my head for me last year and I've done nothing with it since, just let it grow at whatever angle. My mum still despairs of how 'manly' I am, years after the shock I wasn't gay finally wore off.
No one 'transed' him. I hugged and asked questions later, very aware that rejection at that moment would harm both him and our relationship. I now know from his friends that he knew who he was at four years old.
Afterwards, as he trusted me with who he was, I began to realise that I'd never really understood him. It's a privilege to get to know the real him, and to see how much happier he is.
Would I be happier if he wasn't trans? Yes, because I've seen how much scrutiny he gets, how difficult it's been realising he will get no help from the NHS, and how much danger he's facing on a daily basis. School was bad, with constant threats of physical and sexual assault, but street violence and stalking are huge problems for trans men too.
Trans boys and men are targeted because cis men feel immense anger towards them, and consider themselves justified in attacking them. At school, he was told it "didn't count" if he was touched. There have been many instances of 'corrective' rape (a repulsive term) to 'remind them who they are'. His androgyny is always noted, and he has had many men try to grope him. He is eighteen years old.
I worry constantly that he will never come home. While I am totally supportive of who he is, having seen the difference in him since he came out, the fear is very difficult to live with.
But having seen him cope with the difficulties of living as a trans boy and now as a young trans man, I now know there was nothing I could have said which would have stopped him being trans. I would simply have lost him, and we would both have been profoundly unhappy.
No one would be trans unless it meant everything to them.
I mean this in the kindest possible way, speaking from personal experience: please try to accept your child. Life is short, and no one can hurt you like a parent. I hope you can reconcile, but that won't happen until you apologise. You have immense power over your child, and will have hurt them. They will keep you at arm's length to avoid feeling this pain again. You need to regain their trust.
Please use the power you have over them for good, because anything else is abuse. They do not owe you their identity - or their gratitude.
You will never be able to change them. If they detransition, it will not be because you argued them out of being trans. No amount of reading anti-trans hate will bring them back to you.
If my son detransitioned then I would support him just the same, and I hope it would be what he wanted rather than the usual reason - that living as trans became too much of a personal risk.
I wish you well. Please consider the vast power imbalance between a parent and child, and give them the comfort of a supportive parent. As a carer, I know you'll need it yourself one day. Best of luck.