Astronomers use the rate of expansion, the moving away from each other of stellar phenomena as one way of estimating the size of the universe. The other is the distance in time from a point known as the big bang. Using these estimates astronomers place the age of the universe to be between 12 and 14 years. Google puts it at 13.75 billion years.
As for religion, it's not important to me. I neither believe nor disbelieve in God, I simply don't know. It would be nice if a God existed, but I don't know if there is one. And it doesn't matter. What is important to me is the messages that are attributed in God's name. I find them to be useful so I try to incorporate them in my behavior. In my own way I try to love people.
I trust science more than religion because science and technology have affected my life more than religion. I have a warm house in the winter, an android to entertain me when I am bored, and interesting books to read. I am happy with what I have.