No, we don't know exactly what Jesus looked like - either when He was born, or later in life. Artists throughout the ages have tried to picture Him, but even the most inspiring painting of Jesus is still a product of the artist's imagination. The same is true of Mary and Joseph.
Sometimes I've asked myself why God didn't have someone in the first century paint Jesus' portrait (although portraits were rare then, and restricted to very wealthy people). One reason, I suspect, is because He knew that we'd be tempted to turn a portrait of Jesus into an idol - and that would be wrong. It also might have caused us to overlook the deeper meaning of Jesus.
But we do have "portraits" of another kind in the Bible - word portraits! The important thing isn't what Jesus looked like, but what He was like, and what He did for us. And when we turn to the Gospels in the New Testament, we learn these things. Most of all we learn of His great love for us - a love so great that He was willing to die on the cross for our salvation.
Is Jesus Christ real to you? He can be, as you turn to Him in repentance and faith, and invite Him to come into your heart and life. The Bible's promise is true: "To all who received him, to those who believed in his name, he gave the right to become children of God" (John 1:12). Receive Him into your heart today.