Yes, it is a mistake for you to feel this way, because Christ's second coming will be a time of blessing and joy for all who know Him. In that day, the Bible says, Christ "will say to those on his right, 'Come, you who are blessed by my Father; take your inheritance'" (Matthew 25:34).
As you think about Christ's return, keep two great truths in mind. First, no matter how far we fall short, remember that our salvation does not depend on our good works. Our salvation depends only on Christ and what He did for us through His death and resurrection. Your concern is understandable—but never forget that your salvation depends on Christ, not on your good works. The Bible says, "For it is by grace you have been saved, through faith ... not by works" (Ephesians 2:8-9).
The other truth, however, is that God has a reason for keeping you here. Life is short, and if you are ever going to live for Christ, it should be now. Jesus said, "As long as it is day, we must do the work of him who sent me. Night is coming, when no one can work" (John 9:4).
Make sure of your commitment to Christ as both your Savior and Lord. Then make it your goal to live for Him every day, "so that when he appears we may be confident and unashamed before him at his coming" (1 John 2:28).