Jesus himself said that he lived in heaven before being born as a human:
"He that descended from heaven, the Son of man." (John 3:13)
"Because I have come down from heaven to do, not my will, but the will of him that sent me." (John 6:38)
"What, therefore, if YOU should behold the Son of man ascending to where he was before?" (John 6:62)
"So now you, Father, glorify me alongside yourself with the glory that I had alongside you before the world was." (John 17:5)
The Bible says that his origin was “from early times.” (Micah 5:2)
Jesus was God’s first creation...“the firstborn of all creation”. (Colossians 1:15) This means that Jesus is the only one directly created by God. Jesus is also the only one whom God used when He created all other things. (Colossians 1:16) Therefore, Jesus obviously existed even before "all creation" existed.
For more, see
Prov. 8:22-30 "Wisdom" and Christ
Who is Jesus Christ?