The Bible doesn't answer all our questions about heaven, but we do know this: In heaven, we will be with all of our loved ones who have died in Christ. Because of this, I have every confidence that you will not only recognize your sister, but that she will be complete and whole - as will you.
Whenever I am asked a question like this I think of King David in the Old Testament. He was a godly leader - but once as he grew older he disobeyed God and committed adultery with another man's wife. A child was born of that illicit union - and shortly after he was born he became very sick and died. David grieved for him, of course - but he also had confidence that some day they would be reunited. David said, "Can I bring him back again? I will go to him, but he will not return to me" (2 Samuel 12:23).
Some day we will be with God forever if we know Christ - but even now we can turn to Him and know He is with us as our friend. Is your hope and confidence in Him? Make sure of your eternal salvation by opening your heart and life to Christ today.
Then learn to walk with Christ by making His Word, the Bible, part of your life every day, and also coming to Him in prayer, and growing spiritually through your fellowship with other believers. God's promise is true: "Never will I leave you; never will I forsake you" (Hebrews 13:5).