I'm thankful you aren't simply ignoring God or dismissing Him from your life, but that you sincerely want to know the truth. Jesus' promise was meant for people just like you: "Ask and it will be given to you; seek and you will find; knock and the door will be opened to you" (Matthew 7:7).
We know God exists for one reason: He has revealed Himself to us. He has not hidden Himself off in some distant corner of the universe, nor has He left so few clues around us that we'll never know for sure who He is or what He is like. Instead, He has shown Himself to us, if we'll only look in the right places. One of those "places" is the world He has made. Isn't it more logical to believe a divine Creator was behind this complex world than to say it all happened by chance?
But the main way God has revealed Himself to us is by taking upon Himself human flesh and becoming a man–Jesus Christ. This is what we will be celebrating in just a few weeks at Christmas, because in Jesus "The Word [of God] became flesh and made his dwelling among us" (John 1:14).
Do you want to know if God exists–and not only that He exists, but that He cares for you? Look at Jesus Christ, for He was God in human flesh. May this Christmas season be a time of celebration for you, as you welcome Jesus Christ into your life.