I've got all 3 acts a bit more fleshed out, but still a lot of work ahead.

My intent is to have music / sound effects, but not a narrator, so if there are story points that aren't clear please let me know!

Act 1: Starts out with a backstory glimpse of Maria's ice skating. It moves on to showing Selena growing up and catches up with current day with Selena and volleyball. Selena is excelling in both volleyball and school while her mom Maria is working hard to keep her daughter's volleyball dream alive, working and taking care of the house.
Until 1 day when Selena hurts her arm.
(I still haven't gotten the car rides interactions fixed)

Act 2: Selena discovers it is a season-ending injury and is depressed. She even attempts to play because she just doesn't know what to do without volleyball. Maria asks her to come look at a scrapbook of Selena's younger days and all the things she used to do before sports. A picture drops out of the scrapbook of Maria ice skating and when they both reach for it, they swap experiences. Selena discovers her mother's ice skating failures and Maria experiences Selena's volleyball successes and injury.

Act 3: When both realize that they've had an alteration of their athletic dreams, they swap back. They both have more time now to pursue other activities and realize that the past is the past, but the future awaits them and their new dreams.

Epilogue: Future Pictures of Selena graduating, getting married and Maria getting to hold her grandchild. Although their athletic dreams were very important to each at the time, they both realize what is truly important and that is family.