What have you to ask? I’ve got two questions. When did the Holy Prophet, what age did the Holy Prophet start teaching people about Islam? Yes, he was reported to have reached 40, just crossed the age of 40 into the 41st year, when he was revealed by God to deliver his message to the mankind.
The first message which he received was in the verse, in the form of the verse, Iqra, bismi Rabb, bismi Rabb, bismi Rabbika l-lazee khalaq, recite in the name of God who has created, and when he heard this, you know this message was conveyed to the Holy Prophet by the Archangel who is called Jibreel, he came in the form of a human being, but very strong and powerful and gigantic in proportions, he came to meet the Holy Prophet and said Iqra, bismi Rabbika l-lazee khalaq, read or recite in the name of Allah who has created, and he was so afraid, he was awestruck, stricken, that he started trembling and he couldn’t utter a word, then he embraced him.
Then he embraced him further so strongly that Prophet Muhammad sallallahu alayhi wa sallam felt as if he would be left totally breathless, he was squeezed so strongly, so then he said Iqra, bismi Rabbika l-lazee khalaq, and that was the first verse revealed to him, which means, no, no, first he said, I’m sorry, he didn’t keep quiet, he said I don’t know how to read, because the word Iqra means recitation, also to read from something like this, so because the Holy Prophet was not lettered, he was not taught how to read and write, so first he misunderstood and innocently said I can’t read, how can I read, and then he repeated, then he understood, it is not reading what is meant, it is recitation, delivery of message, so he was 40 years old when this happened.