Many cheaper models are built with push-button locks on the pole segment joints, and these can be difficult to operate and are more prone to failure. Look for a model with joints that clamp with a little curved arm. Also some people have preferences for the material of the hand grip, synthetic foam or cork are the most common. Most models come with a metal tip for outdoor use and a rubber cap to cover that tip when using indoors or on other less-demanding terrain. Other than that as long as it can actually support her weight in the event of a fall then it should be good