The JWs ask that question, but it is purely rhetorical. They believe Jesus’ death counts towards forgiveness for everyone. They ask the question to get interest from you so you will want to read their stuff.
If you want to pull the rug out from under her, simply look up the various times the Bible uses the term “Kingdom of Heaven” (or “Kingdom of God”). The JWs are trained to think this Kingdom IS ONLY FUTURE. And the JW is FORBIDDEN to read the Bible on her own, so she cannot do a basic search. But look at Scripture:
Matthew 4:17
From that time Jesus began to preach, saying, “Repent, for the
kingdom of heaven is at hand.”
Matthew 10:7
And proclaim as you go, saying, ‘The
kingdom of heaven is at hand.’
Matthew 11:12
From the days of John the Baptist until now the
kingdom of heaven has suffered violence, and the violent take it by force.
Matthew 12:28
But if it is by the Spirit of God that I cast out demons, then the
kingdom of God has come upon you.
Matthew 13:44
The Parable of the Hidden Treasure ] “The
kingdom of heaven is like treasure hidden in a field, which a man found and covered up. Then in his joy he goes and sells all that he has and buys that field.
Matthew 16:19
I will give you the keys of the
kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.”
What is the Kingdom of Heaven? THE CHURCH. JWs are totally stunned to hear this, and it contradicts their ENTIRE LIFE. They say "Why did Jesus tell us to pray “Thy kingdom COME” if it is already here? ANSWER: The Kingdom arrived first with Christ (Jesus said it “is at hand”), he gave Peter the keys to it, and told parables about it applying right here and now. It gradually unfolds over time, until the very end when it is fully manifest (see
Matthew 13:31-33)
THEN you mention Daniel 2:44 (a super imporant favorite JW passage): 44 And in the days of those kings the God of heaven will set up a kingdom that shall never be destroyed, nor shall the kingdom be left to another people. It shall break in pieces all these kingdoms and bring them to an end, and it shall stand forever
Tell the JW this is a prophecy of the Church and the JW will FAINT. It makes so much sense yet only fits Catholicism!
Read
THIS ARTICLE on Matthew 13 and the Kingdom of Heaven
Do not engage them unless you know what you are doing. Be careful. To do apologetics with JWs YOU have know how THEY think because they are trained to shut down when your arguments get too powerful.