How do i convince my parents to...?

buy me a ticket to a mcr concert. they don't mind the music or anything like thats it because its �35.35 and even though i'm willing to pay they say its too dangerous. My friends are going (their all boys) and if i only got on the train and stayed with them the entire time i would be relativly safe right? i just want some ideas because the concert is in less than 3 weeks. (there are still tickets i've been cheaking) thanks