My DHs niece drinks aged 13. Her mum thinks it's a bit of a joke and tries to half heartedly stop her. Niece is always asking for a drink, making cocktails and generally seeking out alcohol from adults eg her grandmother.
My kids are a similar age, I don't drink and DH does but I really don't want my kids eating in 1-2 years when they're 13. I hate the jokiness of it all around my In-laws. My kids don't seem to be interested but neither do I want them to think it's forbidden. I really don't want them thinking vodka cocktails are ok to drink at the age of 13.