Everyone is treating this girl like she has no clue what she's doing. You're all underestimating her ability to judge a dangerous situation when she sees one. You're assuming that her instincts are not enough to keep her from letting someone who can't control themselves drink from her.
Everyone keeps talking about how she's a teenager and she's a kid, and yet she seems to think that she's an adult. So which is it? Is she a child that doesn't know any better or is she an adult that is capable of making her own decisions?
So don't sit there and tell me to grow up. My problem isn't the fact that you think you're trying to do what's best for her. My problem is the fact that you're automatically assuming that anyone that takes her up on the offer is a blood thirsty animal that can't control themselves. And that she's not intelligent enough to be able to take care of herself.