I watched this on Amazon streaming movies, primarily because it has Molly Ringwald who I have enjoyed since her her teen movies of the 1980s. Here she plays the mom and was about 50.
It is about a New York City family, mom, dad, and two teenage boys, but the movie is mostly shown from the perspective of the older boy. It might be considered his coming-of-age story. The title contains the words "small moments" because that is really what it is about, all those small moments that end up forming your view of the world and molding your eventual adulthood.
Mom and dad are having some middle age marriage crises, the teen boys are dealing with puberty the best they can, the older teen gets very infatuated with a married 30-ish woman who often rides the same bus, while a girl his age at school is taking a keen interest in him.
Yes this is a small movie devoid of any real "action" but as a relationship movie works very well.