But if you teach them good things about Christians now, you should balance it with bad things. At least as much as you balance them learning that on Ramadan Muslims give to charity by telling them what some Muslims do to Jews. I'm just using your standard. Personally, I think it's too young for them to learn any of that stuff - it's hard enough to understand at 26, I can't even imagine learning it at 6, and younger.
Christianity by it's very nature has some balance to it. The whole point is that we aren't perfect and so God had to redeem us.
And she accepted the Lord at age 3, of her own free will. She asked how. Of course her IQ is 149 and she was reading at a 5th grade level by the end of Kindergarden.
My son is 5 and hasn't accepted the Lord yet. I'm constantly having to explain the flaws in evolution to him because he is really into dinosaurs.
I wouldn't have told her about what the Muslims do to Jews, had the dang public school not taught her that Ramadan was good. But it's not too young for them to learn about Christianity.