whatever...now I'm really stuck...the creature grew to approx 6' in length...so by the time it was three years old, how long was it?
Well, Wickipedia says: ‘Several juvenile Psittacosaurus have been found. The smallest is a P. mongoliensis hatchling in the AMNH collection, which is only 11 to 13 centimeters (4–5 inches) long, with a skull 2.8 centimeters (1 in) in length. Another hatchling skull at the AMNH is only 4.6 centimeters (1.8 inches) long. Both specimens are from Mongolia.[29] Juveniles discovered in the Yixian Formation are approximately the same age as the larger AMNH specimen.[30] Adult Psittacosaurus mongoliensis approached 2 meters (6.5 ft) in length.’