SOLVED. YA? Girl travels back in time to island/shipwreck? Meets guy and falls in love? [s]

[Sarah]

I read this book when I was in middle school, 12-13 years ago? It was about a teenage girl who somehow traveled back in time ( I think she hit her head or something) and ended up in the past. I want to say colonial times?

She ended up on an island or coastal area with people who either were shipwrecked or ended up there to settle? She meets a boy a little older who basically falls in love with her/protects her.

There is an evilish older man in this story. I think he is influencing the community and tries to take her for himself if I remember right? I can't remember how.

*Spoiler I think)
The boy eventually gives her his rosary and tries to court her if I remember right. I can't recall.

I do remember thinking the book was called the Devil's Arithmetic but I don't think it was the same one that is so popular now. I wonder if someone put another cover on it?

Can anyone think of a book along this line? I remember just loving the story but I can't remember!!

[Angela]

Could it be The Devil's Own by Deborah Lisson?

[Sarah]

I think that's it!! Thank you so so much! It seems so obscure online now. No wonder I couldn't find anything to match it!