Actually Chi there is a growth chart for it on GameFaqs.com
, and guess what? One of our members created it: dancinkayley.
However, I've found out, by my own experience that the growth progess/process doesnt' follow the exact patter.
For example, I've gotten a Tarakotchi(P1 adult) from a Tongaritchi(P2 teen).
Hope that helps.