Is it normal to cuddle your sister?
Depends.It depends
Yes, cuddling your sister can be a normal, affectionate thing between siblings. It mostly comes down to whether you both feel comfortable with it.
Some siblings are naturally cuddly, while others show affection with a quick hug—or not much touch at all. Families have different comfort levels, and none of those styles is automatically weird.
The important part is that it feels welcome to both of you. If she seems uncomfortable or asks you to stop, give her space; otherwise, a cozy sibling cuddle is just affection.