How can i get my parents to realize I'm old enough to drink alcoholic beverages?

They may be afraid to contribute to you becoming an alcoholic. Also parents tend to revert to being your parents sometimes. It's like what happened to me, when I went back to my home town. I was really good with girls by then, but when seeing one from high school again, I got my old insecurities back and lost my mojo around that girl who was obviously willing.