Advent is a season on the Church calendar. Advent is the four weeks before Christmas Day. "Advent" means "the coming." Jesus' birth that we celebrate On December 25th is not reason of why He came to earth. His life, ministry and death of the cross followed by the resurrection on the third day as the Messiah to deliver all people from sin is reason of why He came. For Christians the Messiah is Jesus Christ and Advent is celebrating His first coming.
Jesus is the only Savior and forgiver and healer of one's sin nature. The time is short for getting the message of Salvation to all people of this world. His Second Advent may be in this generation. All of our lives are, in fact, terminal, so don't put of getting this forgiveness of your sins and the getting right with God. Today is the accepted time. Salvation is already paid for by Jesus and is yours for the asking. How--by your repentance and accepting Jesus as your Lord and Savior.