Well Gidjet skirts are a bit out of fashion but ladies in the first quarter of the twentieth century always wore skirts and rode side saddle.
It was felt unladylike for a lady to wear 'trousers' and modern riding breeches
would have been viewed as being positively indecent.
Riding side saddle is a skill calling for a special saddle but a friend of mine says that she felt quite safe when she used to ride to hounds wearing a long black skirt, fancy leather boots, a ladies top hat, a white blouse, a silk cravat and a button through black jacket.
Imagine riding a horse with one's right leg wrapped around the horn and the left reaching down to a short stirrup iron.