AITA for replacing a borrowed book with a new copy after I damaged my friend's annotated one?

I put the new paperback on my friend Zoe's table. She opened it and said, "Where are my notes?"

I'd borrowed her copy of a novel for a holiday. She asked me to be careful with it. I took it to the beach, put it in a bag with a wet towel, and came home with warped pages and sand in the spine.

I bought a new copy of the same novel before returning it. I thought showing up with the replacement would be better than giving her a damaged book and a promise. I also brought the old one, wrapped separately.

Zoe hadn't lent me a blank copy. There were notes throughout it from a course she'd taken, including things she still referred to. I'd seen them while reading, but when replacing the book I focused on the title and cover.

She says I decided what would count as fixing the damage without asking her. I said the words of the novel were all there, and that sounded dismissive as soon as I heard it.

She isn't demanding an expensive edition. She wants me to stop treating her annotated book as though it was just a worn-out version of the shop copy. I don't know what repair I can honestly offer that would restore the notes to the book she had. AITA for bringing the replacement first?