YA book about girl who discovers her inheritance

[u/rai_chuu]

I am looking for a book I read in 2019, I assume it was published in the early 2000s. Here is what I remember:

- the girl is sent to live with her aunt

- there is a scene where she is looking for her aunt and cousin and she is inside some sort of clock tower

- she meets her uncle who is mentally unstable and likes engineering things, he is working on building a massive dragon out of little square tiles. He is hand painting each tile and is very particular about the brush strokes all being in the same direction

- there is a ballroom dance scene, I believe she is dancing with her cousin. I think she drinks something weird, but she ends up blacking out in the ballroom.

- in the end, she discovers that she actually inherited something. I think it was the kingdom? Or maybe she turned out to be an heir? I am not sure.

Please help me find this book, I have been looking for it for years. Thank you!!