Majestic, mines a bit older, but we did have problems with alcohol. It ended up with me thinking she was somewhere, and she wasn't. In fact, she didn't even know where she was, as in which part of the city, street, etc. I had totally banned alcohol, so she took to lying.
It transpires they are all doing it. If they don't they are not worth knowing. Shit isn't it. So I had to change my stance, I agreed to the alcohol / parties if I could pick her up. She was more than happy with that and has never been legless so far. If I'm picking her up, I may as well have a car full, so I drop off her mates too.
At a party recently a mum sent her 13 year old with alcohol, instead of banning it. To begin with I was horrified, but with hindsight I think she was a very tuned in mum.
I have to work with dd on this one, not against her, as she will put herself at risk otherwise. She did at the party where she didn't know where she was.
Believe me, I would rather have a total ban and heavy consequences for breaking the rules.