The adult villagers' appearance doesn't change as the game progresses. The elderly villagers do slow down, but any other differences you see are simply a result of individual differences in clothing, etc.

Are the females ever too old to breed. I've been trying to use the older ones so that the younger ones can keep working.

Is there a way to make villagers healthy before they actually get sick? I've tried dragging them over to eat or drink well water. If I try to heal them before they're sick they think I'm trying to get them to breed.

Females can breed until they die, but be careful, because if they die while nursing, the baby dies too.

How old do the children have to be before they start being productive members of the village?

14.00

ok thanks ... next stupid newbie question ... is there a period of time where crops do not grow? And does someone need to continue to tend to the field during this time for the next growing season to start?

The farm has a crop cycle much like a real farm. Villagers continue to improve their farming skills as they work the farm, which will come in very handy and provide lots of food later on in the game, when it will be needed.

Next question ... I have an Adept Scientist that I switched over to Trainee Breeder, she had a baby and sat for a while nursing. After a while, I figured it was about time for the baby to be ready scamper off on its own, but I was about to step away from my Palm for a while, and I didn't want mom to immediately drag another villager into the hut and have another baby, so I switched her back to a scientist while she was still caring for baby. I walked away for a bit (it ended up only being about a minute), and when I came back and looked at the map view, I noticed the new little one scampering about. I then went to find my scientist, to make sure she had returned to the research table, and she had - but she's stilll carrying a baby! My population count hasn't gone up beyond the baby I know she was caring for earlier, so is this a bug? Or have the women on my island found feminism and become working mothers!?! While I've been typing this, she's wandered away from the table to go try to push the boulder, still with baby in her arms.

(I finally realized why this company picked their name ... once your boss sees how much time you spend playing all their awesome sim games, it really will be your last day of work .... :} )

Update: about 20 minutes later, the baby disappeared. I wasn't looking at mom when it happened, so I can't pinpoint exactly when/how it hapened...