If the answer above is None it means there is no specific mention in the legislation, but you still need to ask local law enforcement before drinking in Ecuador.
It is prohibited to sell alcohol beverages to a minor under the age of 18 years of age. The law obligates establishments to place a visible notice at the point of sale and to check identification to enforce the law. However it is not prohibited for minors to buy, attempt to buy or consume alcohol.
You can find more legal details and links here:
Wikipedia Legal Drinking Page