Lord Caitanyas brother Visvarupa became an Acarya at age 16 and was known as a great devotee of Lord Narasimha :

[Paramananda das]

Lord Caitanyas brother Visvarupa became an Acarya at age 16 and was known as a great devotee of Lord Narasimha :
At the age of sixteen Visvarupa obtained the post of an Acarya who was an attentive listener of the episodes relating to God, a man of pure, broad and virtuous mind. Being a man of devout worship at the lotus feet of Sri Nrsimhadeva and being of versatile genius and always merry, a man never perturbed in mind, a man always clam and quiet, Sri Visvarupa had no attraction for material world. 1144
Sri Bhakti Ratnakara by Srila Narahari Cakravarti Thakur.
Chapter Twelve - Many childish activities of Nimai
What shall I say about the childish activities of Nimai. He used to be very disturbed if he could not get all the things what he wanted to have.1116
Here while looking at the sky, Niami used to claim the moon from his mother. Looking at the flying bird, he invariably used to claim it from his mother and used to cry for it.1117-1118
All the girls used to complain against Nimai to Sacidevi. All the virtuous brahmins used to complain against Nimai to his father.1119-1120
Sri Sacidevi one day ordered Nimai to quickly call Visvarupa. Visvarupa was then at the house of Advaita. Nimai went there and told his elder brother, `Come on brother, mother is calling you to eat' and holding the border of his brother's loincloth, he came to his house. 1121-1123
Ishana said, "I at once arranged two seats for them and the two brothers took their seats to eat. Oh Srinivasa, I cannot say any more about that incident because my voice has become choked." 1124-1125
Sacimata had tried to make Nimai understand that what he had done was not fair. Sri Murari Gupta in Nadia was a saintly man wand everyone adored him. Saci told her son, "You should not touch the plate of rice of Sri Murari before he has eaten it. For this everyone will criticize you, my dear son."1126-1128
He is a wise man and that's why he does not rebuke you. Please do not do it again.1129
The beginning of Nimai's education
On an auspicious day, Sri Misra gave a chalk in the hand of his son for beginning his studies and writing. he at first wrote the Bengali alphabet and asked his son to write them,. Nimai used to sit with folded legs and write all of them.1130-1131
Having finished his writing, Nimai Chand used to utter the alphabets sweetly which made his father very glad. During his boyhood, Prabhu always used to absorb in his study and used to become very restless if he did not have anything to write. 1132-1133
He gradually became very advanced in writing seeing which everyone became very delightful. Sri Jaganatha Misra took the great pleasure in educating Visvamvara. he used to open a book before Nimai which he used to accept very eagerly and to remain absorbed in it. By standing at this place Visvamvara Rai told his mother to maintain the day of the new moon (Ekadasi). Sacidevi became very glad and took the effort of maintaining the day of the new moon (Ekadasi vrata).1134-1138
Jagannatha Misra decided to give marriage to Visvarupa but Visvarupa had realized already that as this material world was not eternal and there was no use to be in this world as an ordinary person, he decided to be an ascetic. He left the house forever for Lord Krsna and took the title of Sri Samkaranya. he first of all went for a pilgrimage. Visvarupa who was a part of Valadeva Himself was a beautiful boy of sixteen when he left the house.1139-1142
In Sri Krsna Ciatanya Charita (1st chapter) Vaidya Murari took the pleasure of singing the praise of Visvarupa who was a part of Sri Valadeva.1143
At the age of sixteen Visvarupa obtained the post of an Acarya who was an attentive listener of the episodes relating to God, a man of pure, broad and virtuous mind. Being a man of devout worship at the lotus feet of Sri Nrsimhadeva and being of versatile genius and always merry, a man never perturbed in mind, a man always clam and quiet, Sri Visvarupa had no attraction for material world. 1144
Here due to the separation of his elder brother, Visvamvara began to weep miserably. Sachi and Jagannatha Misra also began to cry so miserably that moved everybody present there. They began to take the name of Visvarupa repeatedly and to cry loudly. There arose a very painful scene in the house of Misra. Everyone tried to console Saci and Jagannatha and due to the wish of Prabhu they somehow controlled their sorrow.1145-1149
One day Prabhu told his parents that it was a very good sign of having taken the life of an ascetic by Visvarupa because he would deliver his paternal and maternal dynasties from any sort of damnation and sin. He consoled his parents that he would look after then. On hearing this, his parents became so happy that they took their son to their bosoms and kissed his cheeks. 1150-1152
Oh my dear Srinavasa, the sorrow caused by the asceticism of Visvarupa gradually became cooled down in time.1153