@goldenmist - I might be wrong, but I imagine most modern day geisha's come from families with a strong history in the Flower and Willow World. It sounds like something you have to start at a very young age.
Unfortunately, some girls are actually sold into it, as in the book Memoirs of a Geisha. I highly recommend it if you're interested in this aspect of Japanese culture. The only Western woman ever to train to become a Kyoto geisha, Liza Dalby, also wrote of her experiences, which I haven't read but might be worth checking out.