Castleknock College ( Irish : '' Coláiste Caisleán Cnucha '' ) is a private ( fee - paying ) , secondary school for boys ages of the pupils vary from usually 12 to in and around 18/19 .
Castleknock College ( Irish : '' Coláiste Caisleán Cnucha '' ) is a private ( fee - paying ) , secondary school for boys . 
 Ages of the pupils vary from usually 12 to in and around 18/19 .