Am I reasonable to be upset that my sister is copying me to an extent that I consider extreme?

I could not go into detail in the original post but the item I am concerned about is not mass produced. It is a handmade art doll made by a specific artist that I guarantee most people do not know about. She went behind my back to go through my followed list on instagram to find the artist and buy a doll that is very similar to the one I own. She did this because I would not tell her where i got my doll. Me and my sister (both almost 30) like to have unique, one-of-a kind items and she would be irritated if I bought anything that mimicked one of her prized art pieces. We have discussed the matter before and she values owning "original" art as much as I do.

/r/ask Thread Parent