How can i talk her out of drinking?

I am 15 years old, 16 in a half year and i have a girlfriend who is going to be 17 in a month. She wants to party and drink alcohol. I always tell her this is illegal, irresponsible, uncaring, and immature among many among many things. I absolutely HATE alcohol, whether it is under aged drinking or drinking among adults. It doesn't do anything good, there are SO many better ways to spend your time and have fun in my opinion. I wish my girlfriend saw the same thing i do. She always says, ''its not irresponsible if i'm not drunk,'' well yeah it is because its illegal. The bottom line i need a sure way to get her not to go to parties, i hate it and all i do is worry and sit at home and cry because i'm so scared of what will happen. Thank you, i really need an answer for this.