Would you let your teenager drink alcohol? When would you allow them?

I'll let my kids know that I am hoping they won't drink alcohol with friends/classmates until they finish college. However, they can drink alcohol together with family members once they reach 18 years old. This will be time that we'll guide them how to drink responsibly so they know their limits if ever they already reach the time that they are allowed to drink with friends. They should also learn to say no to friends asking them to drink more, if they know that they are already drunk.