I belive in god. I consider myself a christian even though I don't go to church.

Catholic so part of the billion club.
I believe because I feel like there is more purpose to our life
and how the hell did this universe start with motion?

Lol western people will not like your statement lol, the idea oh having Darul Islam, or khilafah is the most taboo especially for people who hate Islam to rise again. For me i am a supporter of khilafah but not agree on violence on some exten.

The mind is a powerful thing. It can literally make people see things that aren't there. For example: http://en.wikipedia.org/wiki/Shadow_person. Ever been half asleep/half awake and think that some "being" is just lurking over you? I know I have, and it freaks me out in the middle of the night. But I know there is no guy just watching me sleep.

By that same token, if you already believe in Christianity, for example, when you have a NDE, your mind may make you "see" Jesus, heaven, etc. It's not closed minded to be "defensive" about what the mind can make people envision, as everything you interpret, as a sentient being, goes through the faculties of the mind. Otherwise, when all people have NDEs, they'd see the same after life imagery, since there is "only one truth". But that isn't the case, is it? You don't see Muslim NDEs seeing Jesus. You don't see Hindu NDEs seeing Mohammed. You don't see Jewish NDEs seeing Shinto gods. Only people who "see" Jesus, are people who already believed in Jesus. Only people who "see" Mohammed, are people who already believed in Mohammed. Only people who "see" Amaterasu, are people who already believed in Amaterasu. 

And all these people exist, yet claim that their belief is the "one true belief". And that, obviously, can't be true

I don't have time to discuss this right now Mohammad, cause I have still have exams :P. But I'll talk about this in detail after I'm done. 

Sure thing

I mean a peaceful Islamic Caliphate. Groups like ISIS or other terrorist Islamic groups don't and shouldn't represent Islam and Muslims.

Many NDEs share the same experiences. There is usually a tunnel, a bright light at the end, relatives or some familiar entity greeting you, life review, etc. Also your refution doesn't take into account Seth meta-physics which explains that who you see in your NDE depends on your faith system because all reality is created. So if you expect to see something you most likely will. At the end of this, there is always some kind of objective experience and afterlife. 

Why not? it was a theory originally created by a Catholic Priest.

http://www.amnh.org/education/resources/rfl/web/essaybooks/cosmic/p_lemaitre.html

btw, I'm Catholic also.

Edit; just realized how late I am to post this. sorry.

I am not familiar with "Seth meta-physics" but what you described seems to be exactly what I was saying: if you already believed something, that will be what you see when you have a NDE. Maybe I'm confused at the logic you're using but to say I didn't take this into account means that it's something I didn't consider and it is a possible refutation of my argument. But you just pretty much repeated exactly what I said.

Life review aka "your life flashing before your eyes" and seeing relatives/friends, that may be an objective experience insofar as everyone who's had a NDE may see these things, but it is of subjective material i.e. your life and your family/friends. It is never objective content. As in, it's not something somebody else would see or at the very least, something somebody else would be able to describe in exactly the same way. We can both look at an iPhone, for example, a have the same conclusion: a rectangular device with a touch screen that's used to make phone calls. But if two people who had NDEs were asked to describe "the kingdom of heaven", there'd be two vastly different answers about that. If they were Christians, sure, they'd both say they "saw" Jesus, but one would say heaven was an endless cloud city where everyone stood in reverence to God, for example, while the other would say there were palaces for each of God's children and the biggest palace was God's (I actually didn't just make these up. They are descriptions of separate NDE accounts that I've read about).  But then, those both would be contradicted by a Muslim having a "life review", seeing his family and friends.....then seeing Mohammed and 72 virgins.