You aren't alone; many people find it hard to talk to relatives about their faith. It shouldn't be that way, of course; if we truly love someone, we'll want to see them commit their life to Jesus Christ so they'll spend eternity with Him in heaven. Paul said about his fellow Israelites, "My heart's desire and prayer to God ... is that they may be saved" (Romans 10:1).
One reason it's hard to talk about our faith with people who are close to us (such as our parents or siblings) is that they know all about us. We know they'll see our inconsistencies, and they might not take what we say seriously. We also may be afraid of offending or embarrassing them, or of giving them the impression that we think we're better than they are (which we aren't).
But whatever the reason, God has given us a unique opportunity to reach our family members for Christ, and we should ask Him to help us overcome our reluctance. After all, the greatest act of love we can ever show to someone is to tell them about Christ and His love for them. Andrew's first act after becoming a disciple was to find his brother Peter and tell him about Jesus (see John 1:41).
Pray for your family, that God will convict them of sin and convince them of the truth of the Gospel. Then ask God to open the door for you to share what Jesus means to you -- and what He can mean to them.