Tell them that, perhaps 7 days to god is a lot longer than 7 days for us. And so, to put a definite date on the universe is impossible to them. I don't know how to be nice to Creationists without pandering to their religion. Just be yourself and hold true to your beliefs. Just agree to disagree with them.
T H E • M U L T I V E R S E • T H E O R Y