sfb: Most of the older JWs I know became JWs shortly after moving to a new country or to a new town some distance away.
My grandmother became a Bible Student in the late 20s shortly after moving to Canada from Norway. The 'sisters' who came out to the farm taught her how to read English and made her feel welcome in a new country. And they promised her that her baby that had just died would be brought back to life again. That was the promise that sealed the deal for her