1) There is no evidence for a god.
2) All cultures have their own religion. What makes any particular one right?
3) I was 10-ish when I realized I was atheist, so 14 isn't too young. You cannot force yourself to believe something that makes no sense. The more I learn, the less I believe too. Critical thinking skills will be your best asset as you grow.
Remember that even though you don't believe, others do. Try to respect the people, if not the religion. Ask questions but don't be rude if it's not necessary.
I lack the belief in a god because I do not see enough evidence to support his existence. It's as simple as that. There are complexities within that such as rebuttals to famous traditional arguments for his existence, such as the Argument from Design. If you are in a position where it is possible and safe for you to get your hands on Richard Dawkins' The God Delusion then I would highly recommend it. It acts as a crash course in all of these arguments.
Remember that the way you word your lack of belief is very important. Atheism is not a belief, it is a lack of belief. Never say that you "believe there is no god." Rather say that you "lack a belief in god," that way theists will never be able to turn it around on you and say it takes faith to be an atheist.
I was raised secular so I don't think 14 is too young to realise your religious opinions. I do think they're still open to change for your whole life though.
I'm at work at the moment but when I have a moment at home later this week I'll post some more precise reasons why I don't believe there is a skydaddy watching us, although I expect a few of the other TA members to jump in before then.
you should clear up for yourself the distinction between the possibility of a creator for the universe, and the different personalities attributed to him.
i feel comfortable agreeing that a "creator" is a hypothetical possibility as long as science doesn't answer all questions. someone could well have been there to flip the switch and start the big bang, or not...
of course it still begs the question - who made HIM? a creator solves nothing- only pushes the question away by a mediator. but the possibility of a creator remains open, and ultimately, it's a completely meaningless question. CREATOR- implies nothing. aliens maybe? we could be some alien kid's science experiment for all we know. in a lack of knowledge, all options are open, and valid.
thus in my view, even if you accept a creator- what does that have to do with Jesus? or Yahweh? or Zeus? while a creator can't be proven or disproven, like Carl Sagan's invisible dragon or Dawkin's flying teapot, Yahweh and Jesus, and all the rest of them claiming the crown of divinity- have all been completely disproven by historians and archeologists. all you have to do is read.
I think it's nice and a good thing that you learn - about - religions. The more the better. If you are being taught well about how many ways of thinking underlie differences in world-views, how they are influenced by culture, geography and ultimately biology/ neurology and how this in turn translates into wildly varying religions and religious practices; where they can be made compatible and where they are in absolute opposition, while all claim to have access to absolute knowledge by means of revelation, you won't need any reasons from anybody to form your own opinion.
Then you already know a lot more about religion and the world than the overwhelming majority of the world population will ever learn in their entire life.
Firstly having been in a similar position i must say well done on having the critical thought and the guts to come out and say that you dont believe what everyone else does. I think that you can never be too young to think.
In terms of why i dont believe i suppose there are lots of reasons:
1) I dont think that the world as we see it requires a god. Natural selection and scientific theories like the big bang negate the need for a creator and as Wassabi says a creator only necessitates a need for a creator of the creator.
2) An omnipotent god or is illogical. Nothing about our existence, the world or the universe shows us any evidence of a supernatural being. Otherwise why does an omnipotent being allow suffering. The typical response to this is to teach us a lesson but any being who would punish innocent people to teach them or others a lesson is one that i will have no truck with.
3) We as human, as all animals are, are imperfect carrying vestiges of natural selection rather than design (for example human eyes while amazing are not perfect since our blood supply is on top of the retina, a feature which reduces our visual acuity). If we are imperfect and are designed in god's image then he must be imperfect. but since he cannot be imperfect by his very definition he is illogical
4) Wassabi mentioned Dawkins' teapot. This should be Russell;s teapot i believe but the essence of this is that i can make any number of impossible claims with absolutely no evidence, that does not mean you must believe them. Religion is exactly the same, there is simply no proof.
5) The bible is littered with inconsistencies, hatred and stupidity and really is no guide to anything. You can find numerous examples of this on the site if you are interested
6) For me the most important is that religion doesnt seem to make anyone better people. If anything it makes people far more narrow minded and hateful. Such anegative force means that even theists should abandon religion, although it is clear that they wont.
I hope that helps. You should also check out the bibliography on the site for more reading or even start with The God Delusion by Richard Dawkins. It may not be the best text on the subject but it is a good starting point which covers many of the general theist arguments .http://www.thinkatheist.com/forum/topics/skepticism-of-religion-an-1
I do not believe because I am a skeptical person.
A skeptic, in some sense, is a person who tries to believe as many right things as possible and as fewer incorrect or uncertain ones. It helps me in my decision making when I know things that work.
There are so many reasons why I don't believe in god(s). Most of them boil down to lack of evidence. I don't believe in any gods for some of the same reasons that Christians don't believe in Allah or Thor or Zues or Mithra.
My suggestion for you is to keep learning as much as you can about all different religions. This is what started me down the path toward atheism. When you really understand how religions developed I think it becomes impossible to see them as anything more than man made inventions and fantasies.
Here is a good video to illustrate my point: http://www.youtube.com/watch?v=MlnnWbkMlbg
lol the last thing I would say is that you are too young to make decisions on religion. A 5 year old can debunk the entire thing by one simple question.
'who made God'?
Would you ask anyone why they don't believe in Santa Claus? The tooth fairy? I put gods in the same categories as these. No evidence , no reason to justify lying to yourself , religion spreads hate and xenophobia , etc.