The basic premise of Timeless by Alexandra Monir (2011) sounded exactly like something I'd enjoy reading:
Forced to live with her wealthy, estranged grandparents in New York City after her mother dies, sixteen-year-old Michele retreats to her room, where she finds a diary that transports her back to 1910--with life-changing consequences.
There's what should be a lovely blend of family history (involving, of course, secrets), meeting ancestors, a passion for music, and her own romance with a boy she dreamt about before going back in time.
Instead, for me, the writing style didn't appeal, and the ending is one of those very annoying "oh, yes; there's definitely going to be a sequel" endings. Not that I cared enough about this first book to read any sequels. . . .
Short sample of the writing, from the beginning of Chapter 2:
When the bell rang for lunch a few hours later, Michele jumped out of her seat, relieved to have calculus class behind her. Math was definitely not one of her strong suits. She threw her textbook and binder into her bag and hurried out of the classroom, heading toward the school's front entrance. Marion hadn't arrived yet, so Michele hopped onto a bench to wait for her. Friends trickled by on their way to lunch, stopping to say hi and share choice bits of the day's gossip.
I'll note this is a book that seems to be everywhere on the blogs right now, and most bloggers seemed to have really enjoyed the book.
My overall personal rating of Timeless is a C.