Is it normal to be attracted to your sister?
Depends.It depends
An attraction or confusing feeling toward your sister can happen, and having the feeling doesn’t mean you have to act on it. Keep clear boundaries and don’t pursue sexual or romantic contact with her.
Feelings can show up without your choosing them, and having one doesn’t make you a bad person. It may be unsettling, but a thought or attraction is not the same as acting on it.
The important part is keeping the relationship firmly within family boundaries. If the feeling is persistent, distressing, or you’re worried you might act on it, create some distance and talk it through confidentially with a therapist.