Floor height and seat height from ground

I think that floor height and seat height from ground is important for short people like me and my mother. Ground clearance usually mean how high the lowest part under the car such as mufflers from the ground. That's is usually lower than the floor height by a few inches. Regular cars usually have low floor height and seat height from ground. Car-based mini-vans and SUVs usually have higher floor height and seat height from ground. My mother is now driving a Toyota Camry 4-door sedan and the lease on the car is almost up. We thought that we should look for a slightly smaller car. I'm not sure if the Scion TB or Toyota Venza car is good for us. Any suggestions?