If your late grandmother could answer your question, I have no doubt what she'd say. She would tell you to start in the same place she started, by giving yourself to Jesus Christ as your personal Lord and Savior.
Let me explain what that means. Our greatest need is to know God–and the wonderful thing about this is that He wants us to know Him! But when we ignore Him and live a life of sin, we cut ourselves off from Him. Just as you can't ignore the law of gravity without paying a price, so you can't ignore God and His will without paying a price.
But God loves us, and He cares what happens to us. He does not want us to die apart from Him, but He wants us to spend eternity with Him in heaven. And He has made this possible by sending His Son, Jesus, into the world to die for our sins. He paid the price for our salvation–the price of His own blood. The Bible says, "For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord" (Romans 6:23).
Don't let another day go by without Christ. Confess your sins to Him and ask Him to come into your life–and He will. Then ask Him to help you grow in your faith through prayer, the Bible and fellowship with other believers. No matter what the future holds for you, you'll be safely in Christ's hands forever.