Work experience, so frightened !?

I have my work experience tomorrow morning at a really, posh, high maintiance spa resort and im terrified! I've never been but my dad has and he says its a really nice place and so are the people, but honestly i am so, so scared and im so confused on what to wear, i dont want to stick out you see, i want to fit in, but all the info the lady gave me was to wear something " NICE" and for it to not be jeans, Im confused at " NICE" . I was thinking either dark denim high wasited shorts with black tights and black flats an then a nice plain top/blouse and white knitted cardy ? thanks!