Choosing repertoire for a competition

My piano lab teacher at my high school wants me to compete in a state competition. Two weird things about this. One I haven’t been playing for even a year. Two, he almost never asked people to do the competition like one or two a year max do it and usually they’re the ones asking.

I have two pieces to pick from
Prelude in C-sharp minor by Rachmaninoff
Danza de la mozo donosa by Ginastera.

Both of these pieces I’m comfortable with. They both played in my strengths and with prelude and C-sharp minor. I have been looking at it for the past couple of months before I even got the offer. However, don’t think I know the entire piece I learned like the first 6 measures and called it a day.