Aang:  This whole avatar thing . Maybe the monks made a mistake .
Monk Gyatso: The only mistake they made was telling you before you turned _ 16 _ . But we can not concern ourselves with what * was*. We must act on what * is*.
Aang: But Gyatso , how do I know I 'm ready for this ?
Monk Gyatso: You questions will be answered when you 're old enough to enter the Air Temple sanctuary . Inside , you will meet someone who will guide you on your journey .
Aang: Who is it ?
Monk Gyatso: When you are ready , he will reveal himself to you .