Caitanya-caritāmṛta 16.4
ei ta’ kaiśora-līlāra sūtra-anubandha śiṣya-gaṇa paḍāite karilā ārambha
[ei ta’ kaishora-leelaara sootra-anubandha shishya-gana padaaite karilaa aarambha]
Blended reading (Sanskrit + English inline)
ei ta’ kaiśora-līlāra sūtra-anubandha śiṣya-gaṇa paḍāite karilā ārambha
At the age of eleven Śrī Caitanya Mahāprabhu began to teach students. This marks the beginning of His kaiśora age.
My note
Source: vedabase.io