Wow, I think I might be attracted to my sister.
Why are you attracted to her? How do you feel about her?
She's a precious sister of mine.
Your sister sounds like a beautiful person, but it's inappropriate to be attracted to your siblings. Stop focusing on your sister's looks and look elsewhere for someone to be attracted to.
I told her that I love her and she said she likes me as well.
She likes you as a brother most likely, and you need to stop making this into something more than it is. You're going to be thought of as weird if you keep finding your own sister attractive.