Why was Mary betrothed to Joseph at a young age?
According to non-Biblical books, Mary’s parents Joachim and Anne were childless. God gave them an extraordinary child in their old age, as He did to Abraham and his wife, Sarah. Joachim and Anne had promised God that they would entrust their child to the Temple for the Lord’s service. So, they brought Mary, when she was three years old, to the Temple and offered her as they had promised before her birth. While Mary grew up in the Temple, her aged parents died. A girl could not continue in the Temple once she attained puberty. So, between the age of 12 and 15, the priests betrothed her to Joseph, whom God had chosen to marry her, and Joseph took Mary from Jerusalem to Nazareth.