Is this a fact or opinion it is wrong for people under the age of 21 to drink alcohol?

The statement that it is wrong for people under the age of 21 to drink alcohol is an opinion. While it is a legal fact in many countries, particularly in the United States, that the minimum drinking age is 21, the moral judgment about whether it is "wrong" varies based on individual beliefs, cultural values, and social norms. Different people may hold differing views on this issue.