OP i feel you ! My child is a similar age.
Tbh i think some people are absolutely in denial. There's so much stuff you can't control and wonderful if your child never wants to drink.
My child never showed an interest in drinking but then all it takes is to slightly widen your social group, have one child who does and they all start thinking about it.
I think an honest dialogue is actually the only way forward because if they want to, they will. I found all sorts of ways of doing things when I was younger and like you ended up in vulnerable situations as a result.
My child hasn't frequently drunk but there have been 2 occasions where it's happened. They haven't drunk to excess and we've talked about the importance of not drinking much as your body isn't used to it and keeping hydrated
They also know if it gets taken too far, they can call me without fear and I will always come and get them.
I've never bought them any as I know there are a couple of friends who bring some and I think the less they have access to the better.
I personally think this age is maybe about building a healthy relationship with alcohol where its not this big awful thing they have to hide as that creates an unhealthy relationship with it. I don't actively encourage it at all and bar a sip of champagne at Christmas have never given them any.
It's a very tricky age and different teenagers show interest in things as different ages. We're all trying to manage it the best we can and I think you acted in a responsible way.
You should be pleased you have an open dialogue with your daughter.