AITAH for not buying my 16 yo niece the books that she wanted for the summer holidays?

So I (F25) Have my 16 yo neice staying with me. Her parents are away on holiday and they've left her with me. I have no problem with that. I can do my college assignments without her bothering me.

She loves reading. I mean loves it. I know what booktok is, she says she likes it. She has bought countless books over the past week.

Yesterday before school she gave me a list of books that she wanted to buy. She ran out of money on her account, and wanted to buy them before the summer. I'll give you the list

-fix her up -the love hypothesis -collide -it happened one summer -float

I went to barnes and Nobel and they had them all so I bought. Just a little treat, they looked innocent enough. When I looked them up, reviews said they will FILLED with spice. So I decided to return them and get more appropriate "YA" fiction that i got from some various blogs

-the summer I turned pretty -this time it's real -better than the movies -a french girl in new york -kisses and crossaints -tweet cute

When she came home. She was excited for the books. I told her that I bought some others because the other ones were inappropriate.

When she saw them she started screaming at me. She told me that everyone was reading those books and that she's 16 and doesn't want to read books made for middle schoolers. I told her that it didn't matter anyway because they are still romance books. She told me that she already read them. So I told her that she was just being a spoiled brat.

She is now not talking to me. I'm firm on my decision, but I want to get some thoughts from other people.