I think 18 is too young to understand the the implications of how you may vote.
Well that's not insulting at all.
Lemme tell you, at the age of thirteen/fourteen I already knew precisely how our national and local governments worked AND how the EU works.
There are people here and elsewhere who are over eighteen who demonstrably don't have a clue about any of the above.
It's not a question of age, it's a question of knowledge and the ability to comprehend that knowledge.