Hippocrates Explains Irenaeus's 'Almost Fifty' Statement

Irenaeus says in Book Two of Adv. Haer. that Jesus was 'almost fifty' when crucified having reached the age of a magister (the original Greek is wanting). I have always thought this should be taken to mean forty-nine years of age and I think this statement from Hippocrates helps clarify Irenaeus's thought - "In the nature of man there are seven seasons, which men call ages; infancy, childhood, boyhood, and the rest. He is an infant till he reaches his seventh year, the age of the shedding of his teeth. He is a child till he arrives at the age of puberty, which takes place in fourteen years. He is a boy till his beard begins to grow, and that time is the end of a third period of seven years. He is a youth till the completion of the growth of his whole body, which coincides with the fourth seven years. Then he is a man till he reaches his forty-ninth year, or seven times seven periods. He is a middle aged man till he is fifty-six, or eight times seven years old; and after that he is an old man." (Philo, On the Creation 105, Yonge translation). It also seems to imply that the 'youth' of Secret Mark could have been thought to be twenty eight years old.