instead of using 911 try calling the local police department
it's not an emergency
this
really all you gotta do is just go on the internet and look up '(your town/city) police department phone number', call it, give your location and situation
it's best to do this just to prevent anything actually bad from happening
my sister and her freinds (all underaged minors) are drinking heavy in the backyard
yeah you probably should call the police (or sheriff's depending on where you are)