And He is before all things, and in Him all things consist.
All things were created through and for Jesus Christ (as discussed in Colossians 1:16). This fact confirms that the One who became Jesus existed before any created thing, whether angelic or physical.
Of course, we know that the Word has existed for eternity—He has no beginning or end (Hebrews 7:3).
“That all things ‘hold together’ (GK 5319) in Christ means that he is both the unifying principle and the personal sustainer of all creation. It springs from him and finds in him its common cohesion and center (cf. Heb. 1:3)” (Zondervan NIV Bible Commentary, note on Colossians 1:17).
For more about Jesus Christ before His human birth, see “Jesus, the Son of God.”