Yea, I am agreeing with you guys now. I remember the last time I was in SF, it is crazy the way people drive with the traffic, small streets and crappy uneven pavement and much more. She should really learn to ride somewhere else before she rides SF. Because when it comes to 2 wheelers, it is not if you go down, it's when if you have never ridden before. If you learn in a good place, that fall will be very minor, and not cause any injuries. In SF, it would be much worse. Any CVT scooter should make it up SF hills. 50 cc would struggle, a 125 to 150+ wouldn't have much trouble.
Overall I would have to say SF is not exactly a beginner friendly city for motorcycles. It also requires experience and knowing how to handle the scooter or motorcycle, not just knowing how to shift or brake. Good luck!