ETA: I seem like I'm leading here. Let me go further. Not all authorities agree on 18 as a marital age. In fact in many countries, including almost all of the US, you can marry younger with parental consent. In Scotland the age is 16. In Asia it's all over the place.
http://en.wikipedia.org/wiki/Marriageable_age
Should you be able to marry at 16? Does parental consent matter at all in this?