Definately girl crossdressing as a boy, afterall the poses showns in the chapter really hint at it, since guys have different hips thanks to our dicks, women have broader hips and this character has female hips.
Thanks for the chapter!
See, this is why you always knock on a door and wait a moment before opening it when you have a roommate. Now the question is whether that's the roommate pretending to be a boy, relative of roommate, or worst case the roommate's girlfriend he's extremely obsessed and overprotective of. Guess will find out next chapter.
@tigerstar186 Most of it is due to MC's mindset of being middle aged even though looks young. Also, why does look younger he still looks like he's in upper twenties. Then there's the jealousy and need to disparage him by the jealous onlookers.