It's from a one-shot called something like "gender bender mangaka gets turned into a girl". I believe the mangaka in question has made a few popular genderswap mangas in a similar artstyle.
Maybe I'm getting whooshed but the girl in the image is wearing a trans flag. So it implies that OP must be stoked that she's transitioned and feels at ease with her body now. Congrats OP!
80% 196 is trans catgirl anarchists. It is known. The rest is femboy bottoms, except for the one bearded top horsecock enthusiast.