Yes, that is correct. Mankind also existed before coming to this earth.
Revelation 12:7-12
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
12 Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
There was a war in heaven before we came to this earth. Satan and his followers were cast out into the earth without receiving a body of flesh and bones. Michael and his followers eventually came to this earth also but they received bodies of flesh and bones. According to verse 11, Michael and his followers could overcome Satan and his followers by the blood of the Lamb. These followers of Michael who once fought again Satan in the war in heaven came to this earth and were subject to death and became mortals. They needed to rely on the blood of Jesus Christ to overcome Satan and his followers.
The knowledge of a pre-mortal existence led the Apostles to ask the following question:
John 9:1-3
1 And as Jesus passed by, he saw a man which was blind from his birth.
2 And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind?
3 Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
One must ask, How could the blind man sin before he was born if he didn't exist? Jesus doesn't put down their question as a false premise but merely tells them that neither has this man sinned nor his parents.
Here are a list of references to the concept of pre-mortal existence:
God of the spirits of all flesh, Num. 16:22 (27:16).
- all the sons of God shouted for joy, Job 38:7.
- the spirit shall return unto God who gave it, Eccl. 12:7.
- Before I formed thee in the belly I knew thee, Jer. 1:5.
- Lord … formeth the spirit of man within him, Zech. 12:1.
- who did sin, this man, or his parents, that he was born blind, John 9:2.
- poets have said, For we are also his offspring, Acts 17:28.
- For whom he did foreknow, he also did predestinate, Rom. 8:29.
- chosen us in him before the foundation of the world, Eph. 1:4.
- subjection unto the Father of spirits, Heb. 12:9.
- angels which kept not their first estate, Jude 1:6.
- Michael and his angels fought against the dragon, Rev. 12:7.