1. According to my teacher, between the ages of 12-14 is the best time to begin dancing. The reasons:
a) Little children have certain bodily defficiencies or immaturities which make certain movements impossible or very uncomfortable, such as the latin hip motion, because their hips are underdeveloped and they do the motion like sticks.
b) Little kids tend to only appreciate things like learning how to ride a bicycle or play baseball, not ballroom dancing.
c) Little kids have a really short attention span and it's really annoying to try and teach them.
2. No, you don't have to be a certain weight. Besides if you go into dancing you'll probably shed twenty pounds anyways.
3. And no, you don't really have to be a certain height, especially if you are a girl. Most guys are not 6'1" (like me... heh..), so it's not like you'll be grossly mismatched with a partner.
da.