I am not worried as it had happened to me when I was kid.
I believe that it is not us who choose our religion /faith.
The good things abt attending church for kids is, give them dicipline, may not : speak, run n run around and have to sit still during the procession, singing together .
It is not bad to train children good conduct.
Lots of benefit out of it.
This below is only my opinion:
To be strong, we have to train ourself to control ourself---> to control our will.
If we were trained since we're kid, even we sort of rebel in some stage of age, we'll back to our "nature habbit".
We can still have good thought, brain still working under "following good conduct" attitude.
As you do not belong to any religion anyway, why dont you read "Wisdom of Lao Tze" ; it's not a religion, it's only thoughts , look for the original ones.
(Iam not Chinese, not Budhist and not Confusiusm, I am not leading you to religion).
You can see how the old wisdoms are, and what's + how the best to imply in todays life.
You still young as yr children are still infants. You may want or need to find MORE means of life. You still have lots of time to pass. If you're paranoid abt religion, that book above lead you not to religion ,
Good luck and relax.