I throw terms like juvenile, subadult and adult around freely but never really considered the detail around what actually defines these age classes. Came across this Royal Society publication that addresses the ontogenenetic stages of non-avian Dinosaurs. A bit technical but I was able to slosh my way through it and get good info out of it. You might find it useful. I fit the old adult in table table 1
20150947.full.pdf
http://rsbl.royalsocietypublishing.org/content/12/2/20150947