I'm a cop and here's how the law works. First, any open container, even empty ones in a car are illegal while the vehicle is in operation. Second, as the driver of the car, you are responsible for anything found in the vehicle. For example, if a cop searched the vehicle and found drugs hidden underneath the back seat, you alone would be responsible. The same goes for alcohol in the vehicle. Third, as a minor, you don't need to be passed the legal limit to receive a DUI. ANY AMOUNT OF ALCOHOL will result in a DUI if you are a minor. Therefore, with your friends drinking, the officer has reasonable suspision that you at least took a sip, therefore you will get charged with a DUI. Probably not a good idea. I would make the trip with no alcohol if I were you.