let me shine light on your epic ignorance.
first of all, back in those days in Arab, marrying young girls was very common, it wasn't considered marrying someone under-age, and this still happens a lot. Nobody in the Muslim community who are proper muslims and follow their faith do this. The prophet did not want to marry Aysha, he only did because it was God's orders. And there is no proof whatsoever, and you do not have it, that he had sex with her till she was of age. So what's wrong with marrying someone that young in a society where it is commonly accepted, to love and cherish that person, and then marry them, what can be a better and closer relationship?. They weren't siblings or anything you know. And she turned out to be one of the most educated and amazing women of the world who has influenced great tides in seeking knowledge, spiritual, scientific and moral.
Now, about the 'finding and killing unbelievers where you see them' part.
See, this is the problem with you bloody trolls, you don't STUDY our religion then just open your mouth about it. That line is from a verse in the Quran. The Quran wasn't sent down all at once, and it is NOT in it's chronological order. See? you didn't even know that. The muslims were oppressed for many years, they were tortured, not allowed to practice their religion. God did not allow them to retaliate, and told them to be patience. then after a while, he gave the order to go to the BATTLEFIELDS and kill them wherever they are after enduring all that pain and suffering.
so...GET YOUR FLIPPING FACTS STRAIGHT. Learn the religions of the world before you talk about them or express your uneducated opinions please. Islam is the most peaceful thing you can come across, the true Islam. Your mind is too brainwashed by the media, it's pathetic. Wake up, they only tell you lies and always will do and they only do it about this religion cause whoever runs the media knows that it's good for us.
Anyway, I hope you learnt from your mistake.