If she is Catholic she most likely won't budge. So you have to, be the man suck it up, and tell her what she wants to hear. You can still make sure the kids are educated, without poisoning them with your knowledge. It is obvious she doesn't really know what she is talking about, Catholic, KJV, Creationism (which one of these 3 doesn't belong with the other 2). If you love this woman, then yeah YOU have to compromise on this one. How big of a deal would it be to take her side on this one? You have to pick your battles carefully, and this one isn't worth it, if the kids are intelligent and educated they will "see the light".
You could always just fake it, convert, and pay lip service to the thing until the kids grow up.