Now that there are going to be other kids there I would go, have fun, a few drinks but maintain. Then I would use the idiot who goes overboard on drinking as an example to my kids. "Look kiddies, if you are an adult it is o.k. to have a drink or but you don't want to be like Melton over there now do you? Picture Melton 3 sheets to the wind, stumbling and staggering. Show kiddies how the responsible adults take Melton's car keys away from him. If at all possible show kiddies how sick Melton is in the morning. This worked with my daughter who came with daddy to pick me up from a bridal shower. We indulged in moonshine with the bride to be. Let's just say that stuff kinda sneaks in the back door on ya! The aftermath wasn't pretty either. She told me later she was to scared to drink until she was 19 after seeing that even, though all of her other friend were out drinking at the age of 14 and 15.