My Twin Sister

I have a fraternal twin sister. She is not as beautiful as me, not as smart as me, not as talented in painting as me, and not as good as me in everything. But mom and dad prefer her. Just because I am an older sister and she is a younger sister. What's even worse is that she pretends to be pitiful and weak every day, and makes things difficult for me everywhere. In the whole family, I am the only one who knows that she is a liar and a demon in human skin.