Okay... So my take on this awkward mess of a manga.
Akira strikes me as brave. Japan is not an easy place for Transgender people, especially those who can't or don't want to 'pass'. For her to come out at that age as well is important in a story sense as well as reasonable. We always see in manga and anime that there's wild or horrible bullying that goes on in middle school and maybe some people go "Nah. They're just kids, they don't really do that..."
Yeah they do. They're especially cruel at that age. I won't go into detail about the stuff that happened to me at that age, just sum it up by saying I had an unfortunate name, to be in an unfortunate place and once got told by someone that he wished I'd died in the car crash we had so then he'd have some cake to eat...
They're monsters.
That changes as kids get closer to being adults. More and more the things inside us build til we can't stop them bursting out without considerable mental trauma and then we suddenly find... Only the really stupid bother to make a big deal of it anymore. The people around us are more concerned with grades and growing up than someone telling the world who they are inside.
Now for the bit that got a few people going on the first page of the comments... Hime.
I think Hime's a bit dumb, but in a good way. I'm not sure coming out is in their future but I'll hedge my bets by using my own preferences to refer to them.
In any case what I saw the Crossdressing sequence as is not so much a statement to the world about gender not being what you wear, but more of a slightly misguided and sweet way of saying to Akira, "If people are going to cut you out because they can't see the you I've always seen... Then hell, I ain't letting you be the only 'freak' in school." They're crossdressing to alienate themselves and draw fire and ideally (unlikely they've thought this far) normalising queerness within their community. So that Akira is just seen as a normal person while Hime is the controversial freak...
Problem is 15yo's are dainty as china in some cases and I have a feeling either Hime is explicitly someone who's always been a crossdresser in private or may actually have been struggling with their own gender for as many years as they've known Akira's.
Who knows. The author most likely... I hope they're Trans themselves, otherwise this has a high chance of getting cringy real quick.
Still looking forward to it all though.