The pouting Micki Silver regretfully gets her wish - that she had never been born - when she visits a magical room of the toy museum and is plunged into a journey through time.
Finally found this book after years of looking. I read it in elementary school and did a book report mobile on it. It's bothered me for years because I'd forgotten both the title and the author's name, and all I could remember was that there was a dollhouse and the main character went back in time to save her ancestor's life.
It nearly feels like time travel reading it again at 26.