I suppose that if 50 is your definition of "old" you might have something of a point. On the other hand, it might be that "wiser" heads voted against Hillary. This is probably also even more skewed given the population density along the coasts. Anyway, the ageist argument is pure bigotry.
Link: http://www.people-press.org/2018/08/09/an-examination-of-the-2016-electorate-based-on-validated-voters/