She is like just a little bit of a tsundere since she somewhat likes Asta but shows her affection by being a little aggresive, like not verbally, as she would just say "Bakasta" or some shit.
For me that is not enough to consider someone a tsundere but I understand what you mean.
Yeah I just seen a dere wiki online and they said tsunderes are just aggressive crushes
Well shes not aggressive but she doesnt wanna show her affection too easily
I'm pretty sure 90% of the people who say Noelle is a tsundere have only seen the anime. In the anime they made up a lot of her attitudes such as the times she punch Asta (in the manga it happens only twice in almost 300 chapters and it was because she was embarresed of her feelings for Asta). Its true that at the beginning she had a cold and a distant attitude but that was because she was raised to hate everyone who was not royalty and that was also a mask to hide her own insecurities but once she began to know the Black Bulls and the rest of the world those prejudices disappeared. Noelle always cared for her comrades and would give her life for them. Think twice before saying that she is a tsundere because she never was.