Thanks for the replies, everyone!
All excellent points; tomorrow after school, I'll show her this thread and see what she thinks.
As far as actually meeting those requirements, I'm a bit worried... She's not afraid of dirt and mud and picks things up quick. She always asks me about how riding went, and seems genuinely interested. The only thing is she is one of those "best or nothing" people. If she doesn't get things right right away and is extremely good at it, she gives up... And, as we all know, you don't get your horse sense in one day.
And I talked to her about exactly what kind of horse she would want. She wants a 5-8 year old quarter horse mare... I'm working on trying to convince her that she needs something a lot older; 15 plus.