Christian Nation?

[Jenny A]

Correct, but before that it was originally founded as a British state and hence a Christian state.

Not really. I'm not disputing that the 13 Colonies were founded as British Colonies as part of Britain. But the 13 Colonies were not the United States. They were thirteen different colonies with differing charters. Nor were they the only British colonies in North America. When the thirteen colonies that became the United States rebelled against Britain they became a new thing with a separate founding. That founding was by an almost exclusively Christian population which had the wisdom to found a secular nation.