Can my child play ‘up’ or ‘down’ a division than their age category?

Players can play ‘up’ with an older age group than they are categorized in. However, players cannot play ‘down’ with a younger age group than they are categorized in.

For example:
Based on the chart below, a player born in 2005 or 2006, which is categorized as U18, could play in U19 as it is an older age group. However, a player born in 2004, which is categorized as U19 cannot play in U18, as it is a younger age group than they are.