As previously mentioned, God fully intended for us to live in the world we now live in; we are here for a reason. Life did not start at birth. We lived with our Father in Heaven (God) before being born. Although we lived with Him, we were not like Him. He has a perfect body of flesh and bone, but we had only our spirits, or our spiritual bodies. He sent us to earth so that we could be like Him.
Part of coming to earth is facing trials. We have these trials so that we can learn to trust in and rely on God; they help us accept the sacrifice the Lord Jesus Christ made for us, as well as help us reach out to our neighbor here on earth. These trials were not possible in the Garden of Eden. If we believe that our Father intended for us to stay in the Garden of Eden, that means that our trials serve no purpose and are expressly against God's will. If this were true, there would be no comfort and no greater meaning to be found in the hardships that we experience on earth. I know that it is true, and I know that the Father teaches me lessons through these difficulties that I would not be able to learn without them, and that is why He wants me to have painful experiences along with the many joys of life.