That is, do you believe eternal life can be a present possession while still in our current form of existence? It might seem an insignificant question, but the truth might have significant implications for me.
Be aware of interwoven concepts. I’ll go backwards. There is the consummation, the summing up of all things in Christ with the new Jerusalem, new heavens and new earth, the end. This is after the resurrection of the body. Also, there is eternal happiness, the beatitude that is our end, the beatific vision, full participation in communion with the Trinity. This is in heaven. There is also that after a person in Christ dies, they enter eternal life, even though they may go to Purgatory. While in Purgatory, they do not yet have the beatific vision and eternal happiness. While still on earth, we have a foretaste of eternal life, a pledge of future glory, the Eucharist. All the sacraments communicate or give divine life. While on earth we have a real sharing in the divine life of the Trinity (notice how that is part of what happens in eternal happiness). This begins when we are born again or born from above, which will typically coincide with baptism, because that is when we receive the Holy Spirit. The Holy Spirit will dwell in us while we are on earth. If we die without this, without life, without sanctifying grace, without being in Christ, we go to hell.
Note, however, that for a Catholic, it is possible to be born again, but fall away after that. During the time we are fallen away, we do not have the Holy Spirit, we do not have sanctifying grace, we are not really alive, we are sort of like disconnected from Christ, who is the life. By grace we must return to God (usually this will involve confession). Then we are again in Christ, with love/charity within us.
I don’t really know which type of life, which concept you are meaning for what your “E” is on the chart. I don’t think you can possibly mean the beatific vision stage, because most Protestants don’t think that begins when you are born again, and I’m guessing you are from a tradition like a Protestant of some type. Right now, a Christian has life, the new life in Christ, and that life isn’t natural, regular life. It is divine or supernatural or something. They are alive in Christ. They aren’t currently dead. So, for me, I see myself as currently alive, and the life I have is a gift of life that stems from Christ, like being a branch connected to a trunk. In heaven my life in communion with God will be more perfect, but Christ is already alive now (He is Risen, Alleluia!), and I am in him, so that life for me is sort of like that life in heaven. It is life in Christ.
I hope that helps a little. I think it depends on what you mean by “eternal life” before I can answer which of these stages is “it” as you would understand it. To me in prayer life what matters is communion with God, and I have small some of that now. So that is how I tend to talk about life.
*
Now this is eternal life, that they should know you, the only true God, and the one whom you sent, Jesus Christ.*