Is it normal to have been drinking since 7 y.o?

I don't know man... For me it's not normal, but my friend said she's and her brother already been drinking since 7 years old with her parents consent (Usually when they have big family party. Her cousin and nephew also been drinking since that age with their parents consent too).
Another friend of mine had been drinking since 9 years old and 10 years old. I don't get it, it's true that I lived at a country where the Muslim are majority. But it doesn't mean that the parent (from all non muslim child) let their children been drinking since young age (On top of that in my country, legal age to drinking is 21 y.o. But I think this law is not run properly). And what make it so sad is, most of non muslim parents did this.

My reason to asked here because ALL of my friends (muslim and non muslim) think it's not strange at all, because they're non muslim(You know that it's illegal for muslim to drinking right? That's why all of non muslim people, whatever their age is, okay to drinking) that's the reason why I want to ask opinion from people from another country.

Thanks in advance and sorry for my grammar (I hope you understand most of it).