How do i get my sister not 2 go 2 the dance/springfling with me/?

how do i get my sister not 2 go 2 the dance wid me ok der is a spring fling/dance n my sis who iz like 16 is thinkin bout goin wid me n i dont want her 2go so how should i bribe her or watev 2 not go without tellin her dont go! i dont want her 2 go cuz if she goes ill have 2 leave early :( n all my friendz r der sooooo.... any1 hav any ideaz??? i dont want to tell her dont go cuz dat would b juz mean lol well idc if im mean i juz dont want 2 say dont go n den she would ask y? any GOOOD ideas???????????????????