No, you're wrong, it IS true that you cant control what you beleive. To beleive something simply means that you think it is true.
If you know something is not true you can't change that. You can wish it was true or you can pretend it's true but deep down you'll know it's not true.
You know, your statement makes me suspect that deep down you may not even beleive in god. You probably know he doesnt exist, you just really really WISH he existed. It's not true that you can control your beleif.