I agree, a comfort type bike will suit her best. Depending on how comfortable she is riding, it might be best to start out with the seat too low. Encourage her to take it really easy at first. I read a site about how to introduce someone to cycling (or back into it) and he emphasized don't let them go faster than 8 mph on the first ride, which should be no more than 4 miles. They can increase one mile per ride, or 5 miles per week. The reasoning was to keep the pain and discomfort level very low, so they'll want to keep riding. Makes sense to me!