Well, you're not alone. Proms make a lot of people nervous. When you're out of your element and all eyes are suddenly on you, you tense up and forget your basic functions like coordination sometimes. But that's not to say they're impossible! Have you tried some practice runs? Get a feel for your moves before you get to the prom. If they're practiced, they'll come to you easier when it's time to go for real. Also, try to stick with people you know. Any endeavor is more comfortable when you have reliable friends around you.
Proms are daunting affairs, but with the right attitude and a little preparation, you too can reign as king when it's all said and done!