Representation

Not all 30-year-olds have extensive knowledge of politics. As a 16-year-old I knew an extensive amount about each of the parties and their policies; I even knew a few hundred politicians and knew what they stood for.
I will not respect any law if nobody in government will represent me whilst making it.
If 16 year olds can work and pay taxes they should be allowed to choose who governs and spends their tax money on their behalf.

I'm not sure if Firstly, 16 year olds do pay taxes... if they do, then they shouldn't be.  
 
However, you be paying taxes. 
 
You are one of the lucky few who, at the age of 16, knew what you were talking about. Most 16 year olds don't. Democracy is about majoritative rule. If most 16 year olds are uninformed and don't particularly understand or care about the results of elections, then they shouldn't get the vote.