FET generally accepts the consensus of the universe's age based on the expansion and background radiation of the universe. Which is to say, approximately 14.56 billion years. We also accept the general consensus of the Earth's age based on geological data and various other studies which is approximately 4.54 billion years.
FET being related to religion is actually a myth created by RET to make FET look less plausible. In actuality, mainstream religion (such as the Catholic Church) has always accepted the idea of RET.