My first two bikes were a 1981 Honda GL500 and a 2003 Suzuki GS500. I'm glad I started small - loved the Honda so much I bought two more in the course of my riding, and would gladly buy another. A newer 250 is an excellent choice. She'll outgrow it within a year or two, which is fine, but in my opinion it's much better to learn the fundamentals on something that's a little less powerful. On a side note - I remember being at Alum Creek practicing for the endorsement I never got and saw another guy there practicing too. He was riding a Ninja 750 or some nonsense and was clearly a newer rider like me. He almost dumped it several times, and couldn't come close to running the course. It may not be a bad idea to get her endorsement on a light, easy to maneuver bike like the Ninja 250. I still kick myself for not getting mine when I had the GS500. That was about the easiest bike to ride I ever owned.