Colored comic/ graphic novel about twin girls but one is a cat

Looking for a graphic novel/comic book/manga. Cross-posted on r/Findabook

This was a comic book/graphic novel I owned in 2015/ish. It was more sized like a comic book than a manga but I think it was Japanese? Idk I was a kid back then.

The main character runs into the cat at a shrine (feeds it maybe?) and the cat kinda becomes obsessed/in love with (platonically) the girl, follows her around and somehow becomes/turns into a human that looks just like her. Than follows her home. The main character's parents are very accepting and excited to have another child and immediately accept the fact that they have twins now. The father worked in the government and forged birth receipt and other papers needed to create a human being out of nothing so they could say they've always had twins.

I think she had like green hair? Not a bright green but I keep thinking green for some reason.

The picture on the front of the book was the two twins like hugging?

I think the full thing was color but it might have just been the first several pages. Again it has been obviously so long since I've had this book I had it in Middle School.

I think the story mainly followed the girl that was now a cat learning to be human and her relationship with the main character who now is learning how to be a sister.