Nowhere in the Bible are we told to pray to those who've gone to heaven before us, or to other heavenly beings. Nor are we to worship them; when the Apostle John tried to worship an angel who had given God's message to him, the angel rebuked him: "Do not do it! ... Worship God!" (Revelation 22:9).
Why is this? The reason is because we don't need anyone in addition to Christ to intercede for us. God loves us, and in His love He sent His only Son into the world to take away our sins and open heaven's door to us. Only one thing can keep us from God's presence, and that is our sin. But on the cross Christ paid the penalty for all our sins–not part of them, but all of them–and now we can enter God's presence without fear through Christ.
This is why the Bible says, "Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need" (Hebrews 4:16, KJV). If you have never accepted Christ, or if you're unsure of your salvation, turn to Him today and ask Him to forgive your sins. Then by faith accept His promise that your sins are forgiven, and now you can come boldly into God's presence because you are His child.
Thank God for your mother's godly example, and that she is now in heaven. But most of all, thank God for His Son, who alone "is able to save completely those who come to God through him, because he always lives to intercede for them" (Hebrews 7:25).