I disagree with this. Two years is a lot in high school. Obviously, everything depends on circumstances so I am mainly speaking in general. There is a hierarchy in high school that puts freshman at the bottom and seniors at the top. A 14 year old would be freshman or perhaps a sophmore. 16 could be junior or senior. The best case scenario could be a sophmore dating a junior. Then there is the groups within a grade. The 14 year old would be older than his/her classmates and the 16 year old younger. That circumstance could very well lead to as large of a social gap as a freshman and a senior. In short, I see very limited cases where a 14 year old and 16 year old would be dating within there own social class.
There are certain hierarchies when dealing with adults too. And even as adults dating across classes can lead to problems. As adults we set certain rules for our companies and our selves to prevent some of these problems. Teenagers have more problems dealing with peer pressure, urges, etc. than adults have (or should). So I don't think that it is responsible to date outside your class in high school and as I said before I think that a 14 year old and 16 year old are almost always in a different class. Emyv1 is the person in question and perhaps she could say if others in the high school would consider them as equals.
I know terms like "hierarchy" and "social class" tend to have negative connotations and tend to hurt people's pride but they were the best terms that I came up with.