Recreational teams are school grade-based and Competitive teams follow the US Soccer standard of divisions by birth year.
Determine your team Fall Playing Age Group based on the FALL grade or age of the oldest player on your team. This means that if most of your players are in 2nd grade come Fall, but one will be in 3rd grade, your Rec team will be playing in the 3rd grade age group. Competitive teams should have a roster of players all with the same birth year (though younger players are permitted to roster on an older team).
Reminder: SFYS doesn't run specific coed brackets, so mixed gender teams will play in the boys' flights.