This book makes a case for why nobody before the age of 21-23 should touch even a drop of alcohol:
I read it years ago so don't make me cite anything from memory. Read it yourself, if interested. I had my kids read it when they turned 13. There's a lot more to the book -- the alcohol part is just one chapter. After reading that chapter, I told them, "It's your brain, so it's your choice." And because of this book, neither one has touched the stuff. My daughter just got through her freshman year without one drop. Why? Because the book makes a very good scientific case that alcohol -- in any amount-- effects the developing brain.