It is important to tell others about the Lord and how you came to know him. But nowhere in Scripture is that a condition of salvation. John 3:16 tells us, “For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.” It does not say, “whoever believes in him and tells others he is a Christian”.
Telling others about Christ is part of discipleship, not salvation. The first thing Christ ever taught His disciples was evangelism. In Matthew 4:19, He told His disciples, “Follow me, and I will make you fishers of men.”