How to explain to gf's family that I'm a Christian nonrealist?

I hope I do not offend anybody here, just looking for some advice.

As I said, I am a Christian nonrealist, meaning that I follow the doctrine of Christianity but interpret it as metaphorical/analogical (meaning I do not literally believe that there's a guy in the sky watching us).

My girlfriend's family is very religious, and as things in our relationship are getting more serious it seems her parents want to talk to me about their concern. They've made it clear they don't want their daughter marrying an atheist.

How can I explain that I follow Jesus and live by the tenets, I just don't believe that there is actually some big guy in the sky or that Jesus literally rose from the dead/was the son of an actual supernatural being?