I have a size 5 foot but i'm also short (5'1)
My pevlis is very small and because she was head down and there wasn't anymore room for her to grow her head was only 31.5cm despite being full term. I pushed her out in 3 pushes (after a long labour) quite easily.
My osteo mentioned to me after the birth that he was suprised I didn't have more torouble considering the size of my pelvis, but apart from having a long long long labour, it wasn't difficult in the sense of needed any intervention at all.