Arkansas

... but looking at the posts on the page, it looks like some guy named Larry Brown, based out of California, who leads a Facebook Group called "Stop Mandatory Vaccination" might have lead the effort. Most of the posts thanking her for withdrawing it seem to be from people who are out of state.

If she uses Facebook to gauge the public, the onslaught may have spooked her. That's especially true if she doesn't check where these people are from ... which would be hard considering there are hundreds of posts.