??parents And Prom??

I am a sophmore at my school. This year is my first year to be asked to prom (moved to new school my freshman year) and my guardians dont understand how important it is to me! They know the guy I wanna go with and I dont think they accept him. After asking, I was told that he had to come over so that they(him and guardians) could talk!! ggrrr..... Even if they allow me to go I wont be able to stay out late at all. This sucks!! I know/hope that I am not the first to have this problem , so someone PLZ tell me how I can convince my strict guardians to let me go and stay out late(spinning the night at a friends wont work). I wish they knew how important it is to me!! HELP PLZ!!!!!!!!!