I was wondering if anyone has had a similar conversation that I had today concerning the debate of whether the earth is old or young.

I was sharing a study I did concerning the word "Yom" (Day in English) as it appears in Genesis chapter one with a fellow Christian at work today. She asked me the following question.
"Are you one of the Christians that believes that the earth is young? If you are it is my opinion that Christians with that view are one of the reasons that non-Christians do not put much stock in Christianity. They believe that it is silly argument."

I gave her an answer, but I thought I would find out if others have had similar things said to them by well meaning Christians.
Regardless of whether or not you have had a similar experience, how would you respond if you did?
Remember, this is a Christian that for some reason has been duped into believing a lie. Which if you are like me, you used to believe in an old earth yourself and didn't see that it displayed an inconsistent hermeneutic.