Sorry to bring an old thread to the top, but I feel like that the OP's question wasn't fully answered.
Alcohol will not be served to passengers under 18 years of age. Consumption of alcoholic beverages brought from outside the aircraft or purchased onboard is against our company policy. We serve inflight complimentary drinks but we reserve the right to not to serve alcoholic drinks if the situation so warrants.
Source. [Searching the web as the father of an 18yo]