I just got the Bella shorts... they're going back.

Batbike: you probably need a small. I'm 5'5", 29 waist, 38.5 hip and the medium fits me. The leg elastic is slightly "sausage making" on my legs and the rise is low (too low for me). Sitting on my bike I feel my back below my waist is totally exposed. Maybe they suggested the medium because of the low rise?
I ordered the Terry T short at the same time. The Bellas have much more compression than the T short. I don't think there is any compression with the T short. Maybe I need a smaller size? These are probably going back too.

BTW in shorts I wear a medium in Sheebeest, PI, Sugoi and Descente.

I order by hip measurement.