MYTH: Drinking is just a phase all kids go through; they’ll grow out of it.

Actually, many don’t.  In fact, the earlier someone begins drinking, the more likely they are to be alcohol dependent in later life.  More than 40 percent of individuals who start drinking before the age of 13 will develop alcohol abuse or alcohol dependence at some point in their lives.⁵  Ninety-five percent of the 14 million people who are alcohol dependent began drinking before the legal age of 21.⁶

References
5. Grant, Bridgett and Deborah Dawson. “Age at Onset of Alcohol Use and Its Association with DSM-IV Alcohol Abuse and Dependence.” Results from the National Longitudinal Alcohol Epidemiologic Survey.  Journal of Substance Abuse 9 (1997): 103-110.
6. Substance Abuse and Mental Health Services Administration. “Alcohol Dependence or Abuse and Age at First Use.” Washington, DC: Department of Health and Human Services, Office of Applied Studies, October 22, 2004.
Read the full study here