14 is too young to give up on parenting your child.
Why do they want to drink - to pretend their older? So the cool kids will think they're cool too? To act as a social crutch to overcome shyness? To get pissed?
Whatever the reason is, you've condoned it, and they'll drink when you're not there to supervise.
In my day it was creepy older guys who'd buy teen girls drinks, not their parents.
You need to change the rules on this - tell your daughter that you've realised it's too young, there are good reasons, they've been linked by a pp.
And talk to her friends parents and share the info on the dangers of early drinking with them, and say you think you all need to rethink.
Your daughter is 14 - she shouldn't be hanging around the streets or parks at night. You should know where she is - which at night should be a friends house or youth group, and she should have a curfew.
It's not a choice between getting blackout drunk at a party or drinking wine with her friends in her back garden. Not drinking is an option.
I started drinking at 17, and drank a lot in college, getting myself into some very risky situations, and coming across creepy guys who say drunk girls as easy targets, which lets face it, drunk girls are!
Younger drunk girls don't have the maturity to get out of dangerous situations - they want to appear mature, or they don't know how to extricate themselves. It's why grooming gangs get the girls drunk.
If you've read the evidence on young drinking you'll know that early drinking at home leads to more early drinking outside the home, so your daughter will end up in risky situations, which she hasn't the maturity to cope with.