You are correct; 1 Peter 3 does not give that specific information:

1 Peter 3:18-20
For Christ also died for sins once for all, the just for the unjust, so that He might bring us to God, having been put to death in the flesh, but made alive in the spirit; in which also He went and made proclamation to the spirits now in prison, who once were disobedient, when the patience of God kept waiting in the days of Noah, during the construction of the ark, in which a few, that is, eight persons, were brought safely through the water.

However, from other scriptures, we know that Jesus is presently with the Father, and that for Christians, to be absent from the body (deceased) is to be present with the Lord:

Acts 7:55-56
But being full of the Holy Spirit, he gazed intently into heaven and saw the glory of God, and Jesus standing at the right hand of God; and he said, "Behold, I see the heavens opened up and the Son of Man standing at the right hand of God."

Luke 23:43
And He said to him, "Truly I say to you, today you shall be with Me in Paradise."

2 Cor 5:8
we are of good courage, I say, and prefer rather to be absent from the body and to be at home with the Lord.

From these passages, we know that Jesus has taken His own to be with Him. It just wouldn't make sense for Him to take home those who pass away now, but leave all the former saints waiting in "the Bosom of Abraham", as described in Luke 16.