Alexander Rozhenko, son of Worf of the House of Mogh, was born on SD43205, 304 stardates after his conception on SD42901. This gives the Klingon (or at least the 3/4 Klingon - his mother Keh'Leyr was half Human) gestation period as 111 days. When he appeared on the Enterprise-D he was 1041 stardates old, or 1 year, 15 days old. Actor Jon Steuer was 6 1/2 years old (born March 27, '84). When he returned to live with his father on the Enterprise, he was 2172 stardates old (2 years, 2 months) and was played by 9-year old Brian Bonsall (born Dec. 31, '81). When he joined the crew of the Ch'Tang in Sons and Daughters, between SD51096 and SD51145 (call it SD51125 to split the difference), he was about 8220 stardates old, or 8 years 2 1/2 months. Actor Marc Worden was 21. Actor Michael Dorn was 41 when Worf turned 30 in Parallels.

All this just goes to show that Klingons grow up faster than Humans do - much faster at first, slowing gradually. Of course, this makes a certain amount of sense, given the harsh conditions under which Klingons evolved, conditions so harsh the Klingons also evolved the brak'lul to survive. Their development (and thus aging) slows to roughly Human standards by maturity at about age 10. Beyond that point, we really don't have a great deal of information. It would appear that the aging process may even slow further - when Kor, Kang and Koloth appeared in Blood Oath, they were still in good physical condition, and Odo estimated their age at about 150. Kor himself began to go into a bit of a decline a couple of years later, so it can probably be assumed that this is about the limit of the Klingon life expectancy, although given the fact that most Klingons die of other than natural causes this may be a moot point.