Should I wash my hair the night before prom?

Prom is tomorrow night and I’m wearing my hair half up – half down. My hair is very dry, thick, and curly so I can go days without washing it, but I had a game tonight and it has dirt in it and it hasn’t been washed since Tuesday night. Should I go ahead and wash it or just brush it and leave it alone?

Also, if I should wash it should I straighten it or just leave it alone?
-Thanks!