That’s a great question! If sin is a willful decision to move away from God’s way for life, then doubting is not a sin. Doubting is when we have questions about God, and that’s perfectly good and normal in our Christian faith. God made us, and He knows we don’t know the full story of His plan for all of creation, so our questions are no surprise to Him.

I’ve come to realize that doubt can be good, because it can help me leave behind wrong views of God. We can have questions about God, without falling all the way into skepticism and unbelief. That’s why someone smarter than me once said, “The opposite of faith is unbelief, not doubt.” We find answers (historical and scientific evidences) that drive us to the Gospel. God is big enough to see us through our doubt!