Eternal life begins when we rightly see ourselves as sinful, in need of forgiveness. When we understand God's demand on us, "be perfect as your heavenly Father is perfect," we see that God is utterly holy and we are not. He cannot be at peace with or receive sinful people into His eternal kingdom without a mediator.
None is righteous, no, not one; no one understands; no one seeks for God. Romans 3:10-11
Jesus our mediator, who is the eternal Son of God, became the God-Man 2,000 years ago. He lived a perfect life fulfilling all of God's highest demands. He offered Himself a sacrifice on the cross dying in the place of sinners. The wrath and punishment of God that was due to believers was instead poured out upon Jesus resulting in our being at peace with God the Father. He rose again from the dead after three days so that we, too, can live eternally with the Father.
For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit. 1 Peter 3:18
We receive this gift through faith:
Truly, truly, I say to you, whoever hears my word and believes him who sent me has eternal life. He does not come into judgment, but has passed from death to life. John 5:24
Now is the favorable time; behold, now is the day of salvation. 2 Corinthians 6:2
It is our hope for you to now accept these truths as true for you, and to receive Jesus as your own mediator and savior.