I have a hyooge crush on my older sister
its weird to have a crush on a sibling.
I enjoy her company very much, she makes me happy.
It's gross to be romantically interested in your old sister like that. You need to seek help if you're having these kind of feelings.
It's not gross since she has a perfect body.
Her body is irrelevant in this scenario because she's still your sister. Being attracted to her and wanting to do something romantic is incest. Incest in society is seen as disturbing and not allowed.