Prom appropriate dress (Cambridge - Porter Sq area)

Our daughter is seeking a prom dress (size 10/12 or M/L)

Her vision: probably long vs short, interesting neckline but no deep plunge, rich color rather than pale, no big side slit, no long sleeves.

Loved ones that swirl when twirling

Also enjoys vintage

She wants something to feel special in as she rarely has an opportunity to dress up.