which is exactly the mistake I made when I got my 4th generation Prius three years ago.
Once inside it's very comfortable, but to get the superb aerodynamic drag coefficient (0.24, which at launch was one of the 5 best world production car figures) one thing they did to achieve this was to make the car lower.
After about a year I started having hip problems (I'm now 63) which have got steadily worse to the extent getting in and out is now very painful and puts awful pressure on my hips due to the clumsy way I have to do it.
It was until the last 6 months that in discussing with my GP Practice's physiotherapy team that the car may have aggravated or even caused the problems. Reluctantly, I've arranged to trade the car for a new RAV4 Hybrid which is currently somewhere en route from Japan (I hope!).
Interestingly, two other (slightly older) friends have recently had to change their choice of car for the same reason.
Ironically, when I bought my first Mk 1 Prius in 2002, the floor and seats were much higher, and somewhere in the marketing material was a diagram that showed how this made getting in and out much easier!