P.S. I just realized that you only have a few days before the prom. So, focus only on a few more or less core basic steps, try to get together with one or more likely partners before the prom and try dancing together to music of the type that is likely to be played most often, and, I know that this may well sound silly, relax, smile and laugh. Go for the fun. Don't worry about whether you do the steps exactly "right" or not, only whether you and your partner can function together in a more or less reasonable way, and, again, go for the fun of it. Some of the music will suggest various forms of expression in the dance (not just steps, but spins and kicks and leaps and arm movements of various sorts). Express yourself. Have fun.

If there is a contra dance in your area before the porm, you might want to try to work that in. Contra dancing is a variation of square dancing with couples in long lines.
It's lively, easy and great fun. Virtually every contra dance that I've gone to (and I've gone to a great many) is very participatory, with most folks having come on their on, and the experienced dancers are usually helpful with new dancers. You'll quickly learn to balance and really swing -- great fun, and a limited number of other steps. The dances are called until the dancers get in to the flow, with the caller resuming calling as the need arises. There will probably also be a country waltz or two and perhaps one or two other kinds of dances, often ones in which the dancers really move and swing. The Country Song & Dance Society maintains a directory of contra (and other American)dances across the country, so try the Society's web site for a contra dance in your area. If not before the porm, then afterwards. I'm confident that it will give you skills, build confidence on the basis of those skills, and an appreciation thorugh experience of the joy of dancing. And that joy is the bottom line.