Maybe when Luke closed himself off from the Force, it was ‘awakened’ in the person most likely to find him and bring him back. This person is Rey, who in addition to being familiar with the ship belonging to Luke’s oldest friend, is also close to a Church of the Force, the members of which are busy trying to find the First Jedi Temple.
That may just be the Force for you, but it sure would be nice if there was more of a hint in the original movie.
A hint of what? That anyone can be a Jedi? There’s nothing to in ANH to suggest it’s only limited to an elite few. It’s a religion long since forgotten of which Luke’s father was a member. Nobody believes in it anymore. It’s an energy field created by all living things. All living things interact with it.