This is one of those slow, slice of life japanese movies. It's a genre not everyone likes, while I personally am always looking forward to watching this kind of movies. Hence I might be tad bit biased.

The movie is about a teenage girl who gets confused about her life. Her family is going through changes and her crush on boy next door seems hopeless. She suddenly befriends a strange grandma, and that causes her to rethink her whole life.

There's not a single thing I didn't like about this movie. It's paced very well, the story unfolds slowly but you can tell it was well thought-out. The fantasy element surprisingly fits the whole mood of this movie.
While the story doesn't seem like anything new, the execution makes it stand out. Stories about teenagers often seem juvenile and disconnected from reality, but this movies successfully manages to combine both hopefullness of youth and uncertanity of adulthood.
One thing I think is worth noting is how this story seems to be 'in the middle'. By that I mean the movie shows only portion of characters' lives, they don't seem to be like paper dolls created just to tell this story. Their life is happening pre and post the story being told in this movie. We aren't shown "everything" and have to guess, which adds to this aspect.

I'd say give it a watch if you are in a mood for a mellow slice of life story. I didn't expect to like it so much, it probably will become one of my comfort movies.