How to convince parents to let me go to a concert?

Hey me and my cousion want to go to a Hollyood Undead (a band) concert in New york. (New yorks is the closet place to NJ that they are reforming at). ANd me and my cousin are both 14 so My mom doesnt want us to go to New York. (But My 26 year old sister could prob, take us) . Please Help! How to convince parents to let me go to this concert in New York?!!! I LOVE this band and want to see them live SOOO badly!