I know of Hindu religious concepts, and no, you would not be the last soul in line, I tell you. God is all merciful. He is willing to wait for everyone, because He loves each soul individually and each soul has its own special place near God in God's realm. As for those on their 'first soul life,' that is not something to 'worry about.' That soul could have good karma and get up the ranks to a human body pretty quickly. So being on your 'first soul life' makes no difference, it's your karma that makes the difference of how quickly and intelligently you pass through birth and death until you reach a human body.
Karma, by the way, is the consequences as result of actions. For example, someone who kills someone in one life may be killed in the next, because it is their karma. Good karma may get one a body of a human, which gives them the chance for spiritual realizations. If, in that life as a human, one learns love of God and becomes unattached to material things, then the soul goes back to Godhead, to God's realm (heaven, you could say).
Hey, if you want to know stuff about the soul, read the BHAGAVAD-GITA AS IT IS, by A.C. Bhaktivedanta Swami Prabhupada. He knows what he's talking about.
Quote:
"As the embodied soul passes, in this body, from boyhood to youth to old age, so the soul passes to another body at death. The self-realized soul is not bewildered by such a change."
BG., Chapter 2, Text 13
Quote:
"Know that which pervades the entire body is indestructible. No one is able to destroy the imperishable soul."
BG., Chapter 2, test 17
As to the size of the spirit soul, you asked, it is said in the Svetasvatara Upanisad:
"When the upper point of a hair is divided into one hundred parts and again each of such parts is further divided into one hundred parts, each such part is the measurement of the dimension of the spirit soul." (Svet. Upanisad 5.9)
In the Mundaka Upanisad it is said:
"The soul is atomic in size and can be perceived by perfect intelligence. This atomic soul is floating in the five kinds of air, is situation within the heart, and spreads its influence all over the bod of the embodied living entities. When the soul is purified from the contaminations of the five kinds of material air, its spiritual influence is exhibited." (Mund. Upanisad 3.1.9)
As for where the soul goes, well, in Indian scripts such as the Srimad Bhagavatam, the Bhagavad-Gita As It Is, and various Upanisads, there is a cycle of birth and death. The soul is eternal, and goes from one body to another. Many of these bodies are animal bodies, but depending on the soul's karma, the soul may go to a human body.
The soul is not limited by the human senses, such as touch, hearing, smell, etc. Therefore, we can attempt to conceive in these ways - asking questions like "Oh, does the soul have ears?" is pointless, because the soul is not material, but the body the soul is in, and the body's senses, ARE material.
And yes, the soul is eternal. In the Bhagavad-Gita it is said:
"For the soul there is never birth nor death. Nor having once been does he ever cease to be. He is unborn, eternal, ever-existing, undying, and primeval. He is not slain when the body is slain."
BG, chapter two, text 20
The purport following this text goes on to say that "The soul is not born, but, because he takes on a material body, the body takes its birth. The soul does not take birth there, and the soul does not die...the soul has no past, present, or future...there is no trace in history of his coming into being."
And yes, animals do have souls, as do humans, and plants. And no, I'm not making this stuff up. It's all from various Indian scripts. The Srimad Bhagavatam has it all, but the Bhagavad-Gita As It Is specifically in chapter two tells about the soul.
The soul's purpose is to love God, and the reason we're down here is because the soul has forgotten its purpose. BG Chapter two, text 20's purport, "The consciousness of the individual soul is prone to be forgetful."
The soul IS made from the same stuff as the Supersoul, or God, however that does not mean we are on equal level with God.
As for 'Heaven', well, when you go up there, you don't keep all your material concepts of what is fun - food, sex, drugs, etc. The soul realizes that that is not what it really wants, and joins God in his realm.
The soul is not judged by what religion one believes, but the soul does go up or down in the cycle of birth and death depending on its actions in its lives. There are modes of Passion, Ignorance, and Goodness. Obviously Goodness is the one to go for.
The reason you can't prove the soul is because you're trying to prove it materially, and by science. Impossible. Ditch science. It won't get you anywhere in understanding spiritual things like the soul.