Even calling what happened "rape" is somewhat questionable, except in that it would obviously be statutory rape as defined in many jurisdictions. Rape occurs when someone is subjected to sex against their will and without their consent. From what we saw, Jinno didn't consent (plus it's questionable whether she was even capable of giving consent, based on her age). But it seemed to be something that she did willingly, based on the fact that she was trying to get closer to Kousaka beforehand and afterwards she sought to do it again (though since we got only a few panels of the act itself, it's impossible to say for certain what her mindset was at the time).
but the stickler is that she didn't know they were having sex. you think if she knew that, she would have still been so willing? maybe. but considering the society, her age, and the way she reacted after and at the end of it makes me think differently. if she was so into it why did the author show her covering her face with tears? that feels like shame to me tbh. then again, with what the author is doing to the story, god only knows what it really could have meant.
if i'm being completely honest...atm it feels like the author has no fucking clue what she's doing with jinno lol. we are all looking so deep into this, analyzing every smile and tear and yet...it's probably all garbage. like the author isn't really thinking about the way she's writing and portraying this. just too many mixed signals in this.