It is calculated that he was around 18, although this does not appear to have been specifically mentioned anywhere. It is referenced through other means and correlated to other known dates.
Solomon reign was a good one in the start, but he gradually fell away from God. We can even see in his books the first two it was good, but the third one is after he slipped back.
Solomon was the son of David and he suceded David as the king.God asked Solomon what god should give him and he said he only wanted wisdom only. God was happy that he was not greedy and asked for...