I think that's too many life stages....EA should just stick with Baby,Toddler,Child,Pre-Teen,Teen,Young Adult,Adult and Elder. Having 12 lifestages would take up a lot of memory for the game since you would have to have all sorts of items and clothing for 12 life stages,and it could also be a real pain for EA to fix any bugs that come with having 12 life stages.
12 life stages might also make the game very slow and laggy and prone to freezing and crashing,since EA could put color wheels,open world and Create-A-World/Create-a-Style in the game as well.
If EA just gave us 8 life stages,I'd be fine with that.