My friend was telling me an old story. He used the following lines:
There were two childhood friends, Drupad and Dron. They studied in the same school. Drupad was a prince and Dron was a son of a peasant. Once Drupad promised Dron that when he would become a king, he would give Dron half of his kingdom. So when Drupad became a king, Dron asked Drupad to give him half of the kingdom as Drupad had promised. On this, Drupad replied that he had given that promise in immaturity.
By the sentence he had given that promise in immaturity, he meant that he had given that promise due to his immaturity.
This combination in immaturity looks somewhat weird. Is it a natural way of using this word? Is there a better replacement for this word such as in naivety?