I'm sorry you've chosen to follow your parents in their unbelief, although I respect you for wanting to do what is right. In all honesty, however, this hasn't always been the case; some of the worst crimes in history have been committed by tyrants who denied God's existence and rejected His moral standards.
Instead of arguing or trying to convince you that God exists, however, let me instead ask you two questions. First, if God doesn't exist, then how do we know what is right and what is wrong? Some things may seem more "right" than others -- but how do we know they really are? The answer is -- we don't. The only reliable way to know what is right and wrong, and how we should treat others, is if God tells us -- and He has done this in His Word, the Bible.
My second question is this: What about your children? Will they grow up with the same values you have -- or will they do like so many atheists do, and simply make up their own moral standards? Tradition alone won't give them a solid moral foundation.
My prayer is that you won't close your mind and heart to God. He not only exists, but He loves you and wants to give you hope and purpose in life. We know this because of Jesus, who alone could say, "Anyone who has seen me has seen the Father" (John 14:9).