Oh good that is reassuring! Yes if I just think about it as evening dress, then it makes me feel better. I have the dress already, I like it a lot but just wasn't sure whether it was suitable. The sequins are iridescent so it has a rainbow shimmer rather than silvery (as it appears online) if that changes anything.
Yes I am long and lanky willowy, and floor-length is good as I can get away with flats which will please DH no end as he hates being towered over!