The first Christians claimed Jesus was born of the Virgin Mary for a very good reason: They were absolutely convinced that it actually happened.
Remember, Mary expressed disbelief when the angel first told her what was about to happen. And yet the Bible's witness is clear: "The angel answered, 'The Holy Spirit will come upon you. ... So the holy one to be born will be called the Son of God'" (Luke 1:35). Jesus' first followers knew His mother and His immediate family well, because they often followed Him from place to place. If the virgin birth was only a myth, those disciples would have known it, and neither they nor Mary would have allowed it to be proclaimed.
It's significant that the most thorough Gospel account of the virgin birth was written by Luke, who was a medical doctor. If anyone knew the impossibility of a virgin birth it was Luke–and yet, after careful research, he knew it was a fact. The God who was powerful enough to create the whole universe also was powerful enough to bring Jesus into the world without a human father.
You will only understand the virgin birth of Jesus when you understand who He was: the divine Son of God, sent from heaven to save us from our sins. His miraculous birth was a sign, pointing the way to our salvation. Why not put your life into His hands?