According to popular thought, where Christians go when they die is the same place they will spend eternity. But that's not what Scripture says. Revelation 21:1-4 tells us that after Christ's triumph at the end of the world, we'll live forever with him on the New Earth as resurrected beings.
In the meantime, Christians go to be with Christ when they die. What an encouragement to know your mother is there with the Lord! My mom was one of the closest friends I've ever had, and she's been there for 23 years this week. I can't wait to see her again someday.
Theologians call this place where our mothers now live "the intermediate heaven," and we learn a great deal about it from the apostle John's vision in Revelation 6:9-11: "I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained. They called out in a loud voice, 'How long, Sovereign Lord, holy and true, until you judge the inhabitants of the earth and avenge our blood?' Then each of them was given a white robe, and they were told to wait a little longer, until the number of their fellow servants and brothers who were to be killed as they had been was completed."
Here we see that those in heaven are the same people—only relocated. There's continuity of identity from this life to the next. Your mother is now one of what Hebrews 12:23 calls the "righteous men made perfect."