Well I am on my second gen and for some reason I got a oyajitchi if you mate oldies you get a oyajitchi at the toddler stage but I didn't even mate em this could be random or perhaps a rare glitch but I am confused :o
As far as I know you can only age em but they won't grow If your kikitchi just became a kikitchi you aged it like a snap you would have to wait 3 more days for marrage and 6 more days for oldiness. btw I would not suggest turning your tama into a oldie unless you got 2 tamas 1 male and 1 female...
Well I think that the top is all good care in 1 group and the bottom is gall bad care in 1 group and middle is neutral
for adults. Because I Have 2 tamas I took perfect care of them and my girl grew up into a makiko. And my boy was a kuromametchi. Or like dazzletchi said it could be randomized...