I apologize for dredging up this old question but it contains incorrect information that I thought worth addressing.
The original question contains an unsubstantiated assumption that seems to be shared by those answering.
"If the Almighty God began life as a man, He must have been part of this universe."
This is an assumption and not Mormon doctrine.
Here is what we have on the subject
I am the Beginning and the End, the Almighty God; by mine Only Begotten I created these things; yea, in the beginning I created the heaven, and the earth upon which thou standest.
I took that one from Moses 2. It's mirrorred twice in Genesis. I take it to mean that God created the universe but that's my interpretation. Others take it to mean that God created this earth and the sky; also an interpretation.
I've heard speculation that God created separate universes for each planet He placed His children on (which I thought sounded silly), that each galaxy contains a world with people on it (sounds more plausible but still pure speculation) and several other variants on that theme.
And worlds without number have I created; and I also created them for mine own purpose; and by the Son I created them, which is mine Only Begotten. And the first man of all men have I called Adam, which is many. But only an account of this earth, and the inhabitants thereof, give I unto you. For behold, there are many worlds that have passed away by the word of my power. And there are many that now stand, and innumerable are they unto man; but all things are numbered unto me, for they are mine and I know them.
It's human nature to take the information we are given and make (what seems to us to be) logical deductions and conclusions and then assume that those conclusions are fact. We need to remember where the raw data ends and the interpretation begins.
The scriptures are the raw data and they don't mention the universe by name. They don't tell us about the Almigty God's relationship to anything other than us (Mormons include angels in that 'us'). "Does our Heavenly Father have a father?" Again, the scriptures don't tell us about His relationship to anyone other than us.