The first thing you should've noticed in the question above is it says "when you die", not "if you die". One thing is for certain - everyone will die out of this earthly life as we know it. And death has no age restrictions; people of all ages die everyday. You have an appointment as well - it's just a matter of when. After that, your soul (the part of you that will live forever, and what makes you - you) must go somewhere. The Bible says "...it is appointed unto men once to die but after this the judgment" (Hebrews 9:27). So, where will you (or, your soul) go?
Some teach that no one can possibly know where they will go for sure until after they die. Some teach that you have to continually do certain things in order to "hope" to get to Heaven, and after doing these things - you still don't know for certain. Some even teach that there is no such place as a literal Hell full of fire, brimstone, and eternal suffering. Jesus taught more on the dangers of Hell than anything else. Throughout the Bible Hell is warned against, referenced many times, and described as a literal place of torment. That's why we feel it's important to teach people they can have the guaranteed security of Heaven.
We would like to show you that the Bible actually tells us that we can know - for certain. In 1st John chapter 5 verses 11 through 13 the Bible says "And this is the record, that God hath given to us eternal life, and this life is in his Son. He that hath the Son hath life; and he that hath not the Son of God hath not life. These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God." The apostle John here is simply telling us that we can know without a shadow of a doubt that we will go to Heaven, and all we have to do is believe on the Son of God - Jesus Christ.
Now it's easy to sit here and say "sure, I believe in God" and then go on living a sinful life. This is where God, through His Word, wants us to realize that there is a difference between believing IN Him and believing ON Him. The Devil believes IN God, for the Bible says in James 2:19 "Thou believest that there is one God; thou doest well: the devils also believe and tremble." You must believe ON Him, this means to place all your faith and trust in that He gave His life for your sins on the cross so you may enter into Heaven.
Place your faith and trust in Him and receive Jesus Christ as your personal saviour today, it's easy and it will secure your eternity in Heaven. The first step is to realize you are a sinner "For all have sinned, and come short of the glory of God" (Romans 3:23). Because you are a sinner, you are condemned to death. "For the wages (payment) of sin is death" (Romans 6:23). This includes eternal separation from God in Hell. But God loved you so much He gave His only begotten Son, Jesus, to bear your sin and die in your place. " . . . He hath made Him (Jesus, Who knew no sin) to be sin for us . . . that we might be made the righteousness of God in Him" (2 Corinthians 5:21). Jesus had to shed His blood and die. "For the life of the flesh is in the blood" (Lev. 17:11). " . . . without shedding of blood is no remission (pardon)" (Hebrews 9:22). " . . . God commendeth His love toward us, in that, while we were yet sinners, Christ died for us" (Romans 5:8). Although we cannot understand how, God said my sins and your sins were laid upon Jesus and He died in our place. He became our substitute. It is true. God cannot lie. My friend, "God . . . commandeth all men everywhere to repent" (Acts 17:30). This repentance is a change of mind that agrees with God that one is a sinner, and also agrees with what Jesus did for us on the Cross. In Acts 16:30-31, the Philippian jailer asked Paul and Silas: . . . 'Sirs, what must I do to be saved?' And they said, 'Believe on the Lord Jesus Christ, and thou shalt be saved . . . .' Simply believe on Him as the one who bore your sin, died in your place, was buried, and whom God resurrected. His resurrection powerfully assures that the believer can claim everlasting life when Jesus is received as Saviour. "For whosoever shall call upon the name of the Lord shall be saved." (Romans 10:13). Whosoever includes you. Shall be saved means not maybe, nor can be, but shall be saved. Surely, you realize you are a sinner. Right now, wherever you are, repenting, lift your heart to God in prayer. In Luke 18:13, the sinner prayed: "God be merciful to me a sinner." Just pray: "Oh God, I know I am a sinner. I believe Jesus was my substitute when He died on the Cross. I believe His shed blood, death, burial, and resurrection were for me. I now receive Him as my Saviour. I thank You for the forgiveness of my sins, the gift of salvation and everlasting life, because of Your merciful grace. Amen."
Just take God at His word and claim His salvation by faith. Believe, and you will be saved. No church membership, no lodge, no baptism, or no good works can save you. Remember, God does the saving. All of it! You say, "Surely, it cannot be that simple." Yes, that simple! It is scriptural. It is God's plan. My friend, believe on Jesus and receive Him as Saviour today, it will be the best, life-changing decision you ever make. Believing ON Him and accepting Him as your personal Saviour will change your life - 2 Corinthians 5:17 "Therefore if any man be in Christ, he is a new creature: old things are passed away behold all things are become new".