OP I've forgotten how old your DD is ?13 ?
I've been looking at a lot of YouTube clips of one Noah Finnce - I'm not linking, there are lots to look at if you search the name.
Probably not yet age appropriate for your DD but I have watched a lot in a genuine desire to understand and I can relate to him (I'm rolling over with the pronouns here
call it respect/kindness/not wanting a strike whichever) in some ways because he is a year older than DD2 and a year younger than DD1, seems to actually have thought through and understood quite a few issues with intelligence and isn't in total denial of biology in so far as he cheerfully talks through his life as a girl and medical realities of transitioning etc.
What have I learnt?
Noah went to a mixed boarding school (sports scholarship) with lots of strict rules. You can find a clip about his school years. I've an idea which school and I doubt "progressive" is in the vocabulary.
He sensibly decided not to rock the boat and come out as trans until he had finished school and much as it pained him, knuckled down and wore a skirt.
He achieved a creditable 3 grade Bs. (YouTube fan divulged that information so accuracy not confirmed).
He now seems to be having a gap year to complete transition but hasn't mentioned future plans that I've seen.
So...
He wants to have children one day (hello surrogate Mum of the future) and has had eggs frozen. (There's a video all about it).
During this video he waved pictures of his dream man (future husband) with whom he will have a gay relationship and said children.
He had "top surgery" at the beginning of the month. Seems to have researched a good surgeon and is delighted with the results which you can see on YouTube.
He has thought through "bottom surgery " and isn't prepared to do it, giving very coherent reasons to do with surgical risks and poor aesthetic results. Sensible.
He started T a few months ago and seems happy that his voice has dropped and he can no longer sing like he used to as it shows the T is working. Seems a shame for someone who loves their music, (his brother had a music scholarship to same school) but he's happy, Perhaps he will end up baritone or something. 
Last night I viewed another clip on how to stop your periods.....go to the family planning clinic and get depoprovera injections which coincidentally has the advantage of providing contraception which he advises is important and the nice nurse also gave him a supply of condoms.
So....he says he's a gay trans boy but apparently has piv sex, understands enough biology to know the risks (of pregnancy) etc.
I'm just so confused. Perhaps I'm too set in my cis het ways (I'm using cis ironically here, I hate the word) to imagine a more fluid approach in so far as he says he is a gay guy, appears to have a normal male looking boyfriend and has piv sex. I wonder if his boyfriend thinks of himself as gay. Bi is possible of course but otherwise presumably he's not worried about most of the woman stuff like breasts etc but definitely wants the vag. Maybe that is the future for some of these trans boys. They may have a shock when they all start looking for willing surrogates at the same time.
Not sure what I'm trying to say here or what I have learnt.
I can never support unnecessary surgical procedures, body modifications and long term medicalisation of healthy young people. I think we (society) probably have a long way to go to understand these girls and give them the best help and advice, especially in the current climate of gender affirmative care and denial of social contagion /ROGD etc.
Anyway watch away maybe it will give you some insight and also you can be one step ahead of your DD and the school perhaps.