This is never an easy situation. Some have it easier than others. My mom thought my atheism was a phase when I first told her, but she didn't disown me.

Others have posted here that they were teens stuck in a fundie family and that when they found out they went ape shit.

I can say kudos to you for caring enough about your kids to raise them to think for themselves. But as far as interaction with your family, only you can judge that.

I don't know how your particular community would react to an open atheist, much less your family. But whatever you do, you do have the support of all of us here and whenever you need to talk, we will be here.

I favor this idea.

While some here have mentioned a constant struggle to keep their children religion free, I never had that problem.  My children were all very logical except the youngest who is learning disabled.  (The youngest now attends a church, but he knows I don't and won't believe.  So we skip all the proselytizing.)   My grandson is 15 and a staunch atheist.

I don't know - point out science everywhere.  I always started with "kitchen" science -this is a mixture, this is a suspension, this is a solution.  The proteins in an egg denature when you cook it, that is why it turns white and solid.  This is how thermodynamics is expressed when cooking dinner.  Point out evolutionary adaptations and imperfections.  The age of geological formations in your area.  If you are a little short of knowledge in some areas, admit it, and go research together.  And most of all, don't dumb down what your child read, stretch their reading abilities with good, solid science.

Maybe it was reprehensible of me, but I also mentioned what a shame it was that some people were so delusional as to believe in religion and imaginary friends.  They were/are nice people.  Some are our relatives.  But I just couldn't/can't see how they can believe in such silly things.  Make sure your children are old enough before you say this so they don't blurt out something in front of the relatives that may upset everyone.

Welcome to the boards and best wishes for you and your family.

Welcome to the forum, Scavner.

These are my suggestions. Take them with a grain of salt. 

Without your daughter as a factor, it is not very difficult to stay hidden indefinitely. In general, your family and community will assume you're a Christian, because they want to, unless they have overwhelming evidence that you're not. However, you can't be completely silent towards your daughter or she will grow up in a fundamentalist Christian community without any dissent; in that case, it is incredibly hard to break conformity and many people who would become skeptics in a more diverse environment will squash their own doubts out of practicality. And, once you begin influencing your daughter, I think people will know about it because she is a child and will say things. So, I don't think conflict can be avoided here, as long as your family decides to start a conflict once they realize that you are saying unChristian things to your daughter.    

If you want to keep yourself hidden for a little longer, it is okay to take your daughter to church or Sunday school occasionally, maybe even beneficial, as long as you are there to offer a second opinion when she has questions and comments. Just for her to know that you don't agree with the rest of the family, that you're a dissenting voice, that is what's important and extremely powerful.

Overall, try not to be confrontational, but be honest when your family starts becoming suspicious. If they are fundamentalists, I'm sure that they will be at least somewhat irrational and hypocritical when this issue comes up. I would try to remain passive; the goal is to have permission to influence your daughter and avoid conflict rather than win an argument (you'll never win. it doesn't matter if you're right and poke holes in everything they say.). After people know, you'll always be judged unfairly, so to make the best of it, you really have to be a sort of "model citizen." 

While it is fair to say advise will be given on a variety of points of view. I myself try not to give advise outside a situation I am not living myself.

I really only address teens stuck in fundie families to tell them they will get old enough someday to live on their own but until then they still need food and a roof over their heads. And as such would be better keeping the peace by avoiding the subject and taking their therapy with like minded people outside the earshot of their family. Stay in school, get good grades and stay out of trouble.

But other than that, just like for gays, although it helps the more people are open atheists, we do not know others day to day life or what complications or conflicts can happen. Bottom line, there is no blanket solution to an atheist's problems living in a hostile environment.

I can only address what I would do in a given situation, and even then, many times in reality, what we say we would want to do, doesn't always translate into what we actually do.

To the atheists who are silent with their families or in their communities, just know you always have websites like this when you need to talk. Only you can gauge best how to deal with a situation. But you will always have some sort of online atheist community a support.

Welcome to the forums.

Unfortunately, I don't know much about the current governmental or social situation in South Africa (or most places outside USA, really).

How about the community?  Would opening up as an atheist result only in being disowned by your family, or would it also result in substantial problems with the rest of the people where you live?

My mom's family has more or less disowned her over the years (it was kind of gradual), but she's made a lot of friends in the community that help fill the roles that family normally fills at her age.

Depending on the social environment and the particulars of your family's belief system, you could also consider setting up some type of disguise.  I used Unitarian Universalism when I was a teen.  I spent two years attending a Unitarian Universalist youth group, and form the day I started until my parents discovered I was an athiest some four or so years later they never bothered me with concerns for my "spiritual well-being."  They just saw me going to church every Sunday and they didn't seem to care what the religion was as long as I had some kind of religion.  That kind of thing is rather common here, but for all I know it may be unheard of in your location.  And if your family is fundamentalist, this won't work very well.

 This certainly is a tough situation and wish you all the best. I too want to be careful with advise since I know little of your circumstance (or even country) except what you have written above. Is there a wife in the picture? Does she think like you?

Here is some things for you to consider and but always take the course of action that is right for you. As they say in boxing "Protect yourself at all times" and that includes your daughter.

Teaching her science is a good idea. What is the scientific method? Teaching her how to think and not what to think seems to me it can only be beneficial. I find astronomy a wonderful subject that anyone can appreciate. It is a fact that the stars are millions of light years away. (You don't have to say why does the bible say the earth is only 6-10k years old).  Are there science  museums you can take her too? 

In my thinking I wouldn't want my young daughter to feel the wrath of any fundie because she asked an innocent question that might mean she doesn't believe their BS.

It might be good to teach how to handle and resolve conflict. She doesn't need to defend anything. Part of being mature is know there is not just one right opinion and it is OK to let it go when you see there is no point or even worse. Loving someone in my opinion is letting them be who they are, but I must stand up for myself when a line has been crossed.

Please do continue to tell us here how it goes. It can help you understand how you are feeling by writing it out and in return you might get some thought provoking questions or advise that will help you.

Cheers.