As a female, that rides a 250, I would say definitely start her on one of them. I have had my 250 for over a year now, and it was great to learn on. I admit that after a couple months it always felt lacking in power on the straights, but I am a pretty aggressive rider, and still have a good time on it. It will be worth it to learn on a smaller bike, she won't be so overwhelmed. Plus, she will probably drop it (not probably, she will)and plastics for a 600 are a lot more $$ than for a 250. Also, if you spend a lot on a 600 for her she will probably get all psyched out and nervous about putting scratches on a pretty bike. I bought the 250 for $900 and can easily get that when I sell it this spring (or whenever I find a good deal on a 600). Now I ride the hubbys 03 636. I have a blast on it, but think it would be very overwhelming for someone that has never driven a bike.