I was worried, for a moment, how this book would go. It’s difficult to pace a book when you’ve got two storylines going because you’ve got to move them at a different pace. Events that your storytelling muscles tell you should happen at 100 pages—

like Alice having her “I’m a vampire” realization

— are happening at 200 pages. The book, however compelling I found Sabine, dragged. 
But the second half.

Once Sabine met Charlotte, I really felt like the pacing was picking up, although I found Sabine the most compelling character to follow throughout the book anyway.

The second half was VE Schwab at their finest. Messy, complicated characters and lovely words and stunning choices that left me breathless. 
If you’re struggling with the pacing the first 200 pages, I understand. And normally I hate to say “just wait! it’ll pick up!” But I think this book is really, really worth it.