The most suitable age to have a right to vote

The essay is supposed to contain: the introduction, three body paragraphs and conclusion paragraph. Also it supposed to be an argumentative essay type.
The topic “The most suitable age to have a right to vote” is basically a title to talk about “Why this particular age is most suitable to vote”.
First body paragraph – differences
Second body paragraph – discussion (sources as many as you want; articles, quotes from books…)
Third body paragraph – my own opinion (in this case: yours)
Basically, each paragraph has to have different perspectives.

My essay writer is not supposed to talk about just one particular age, but have proof from all kinds of trustful articles or books, to prove that, for example: 16-18 is the most suitable age to vote some countries, but maybe in other particular countries 20-25 is better, well, something like that.

Please, note that I am not a native English speaker and try not to use big words and just write the essay in a simple but University level English. Also, note that I am a European and I live in Lithuania (you don’t need to write about Lithuania).

Don’t write any unnecessary information about irrelevant European countries, try to focus on the most relevant ones and especially UK and USA.

In the conclusion paragraph you can either talk about how the right age to vote depends on the country or if you choose to talk about, in your opinion, the most suitable age to vote in a third body paragraph, just end it with your arguments why.

Despite all that, you are free to write about any age you think is suitable to start voting, you have a free will to give your own opinion.