We existed in some form before God created us as the beings that we are now.
ALL HUMAN BEINGS—male and female—are created in the image of God. Each is a beloved spirit son or daughter of heavenly parents, and, as such, each has a divine nature and destiny. Gender is an essential characteristic of individual premortal, mortal, and eternal identity and purpose. [The Family: A Proclamation to the World]
Our gender, male or female, is an essential part of us that has been since before we were created as human beings.
What is the purpose of earth life?
And I, the Lord God, spake unto Moses, saying: That Satan, whom thou hast commanded in the name of mine Only Begotten, is the same which was from the beginning, and he came before me, saying—Behold, here am I, send me, I will be thy son, and I will redeem all mankind, that one soul shall not be lost, and surely I will do it; where fore give me thine honor.
But, behold, my Beloved Son, which was my Beloved and Chosen from the beginning, said unto me—Father, thy will be done, and the glory be thine forever.
Wherefore, because that Satan rebelled against me, and sought to destroy the agency of man, which I, the Lord God, had given him, and also, that I should give unto him mine own power; by the power of mine Only Begotten, I caused that he should be cast down;[Moses 4: 1-3]

Our life on earth is a continuation of the battles in heaven. Satan tempts us to join his side, God and his Son invite us to follow them in order to receive blessings now, and return to Him and enjoy many blessings in eternity. Here is where we choose the life that we want to have forever.
For behold, this is my work and my glory—to bring to pass the immortality and eternal life of man. [Moses 1: 39]
Honor to God isn't bragging rights, trophies, or admiration. His glory comes when he can exalt his family to live with Him with life eternal.
And he that receiveth my Father receiveth my Father’s kingdom; therefore all that my Father hath shall be given unto him. [D&C 84:38]
How does life on Earth prepare us for Eternal Life?
Experience, trials, connection to others- God's plan does not involve leaving us here on our own without help. His power is not only on this earth, but in each of us.
The
September 2015 Relief Society Message testifies of Jesus Christ as one who is powerful and full of glory. It asks women to consider the question, "How does the power of God arm us with power and glory?" The first reference suggested for further reading is a Priesthood session talk. Why do you think they would put that as a reference for an article directed at women?
What is the priesthood?
The priesthood is the eternal power and authority of our Heavenly Father. Through the priesthood, God created and governs the heavens and earth. Through this power He redeems and exalts His children. [Come Follow Me Young Women Lessons, June]
Do men have this "eternal power and authority of our Heavenly Father"? Do women?
Why do we, in the church, often compare Motherhood to Priesthood, instead of Fatherhood?
What callings would you want? Nursery Leader? Sacrament meeting greeter? Bishop?
We shouldn't spend our energies pining after a calling, and understand that the Lord with help us to fulfill whatever He asks us to do (
see 1 Ne 3:7)
He will help us to fulfill our callings as men and women, too.
In order to have harmony, there needs to be at least two parts. Women and men have unique qualities that compliment each other without 'being' each other.
In addition to helping each other, our roles strengthen us as individuals.
We are not here to compete, but to complete each other.
We don't always know why the Lord has created his plan the exact way that he has, but we can find the meanings when we fulfill the roles that He has told us will help us fulfill our potential.