Liberal thinkers try to say that young girls were married off at extremely young ages in Bible times (like the age you mentioned 12, 13,- 16), but we do not see that at all as the general rule in Bible times. God Himself set the age of being accountable for life decisions at 20 years old. Numbers 14:28-30 says, "Say unto them, As truly as I live, saith the LORD, as ye have spoken in mine ears, so will I do to you: Your carcases shall fall in this wilderness; and all that were numbered of you, according to your whole number, from twenty years old and upward, which have murmured against me, Doubtless ye shall not come into the land, concerning which I sware to make you dwell therein, save Caleb the son of Jephunneh, and Joshua the son of Nun."
That age, 20 years old, applies solely to men. At that age, 20 years old, a man can marry or being a soldier. Not before.
But, such age, 20 years old, doesn't apply to women.
Actually, in the middle of the desert, men were the ones murmuring against Moses, not women. Men were the ones sent to fight as soldiers, not the women.
Maybe that is why Jacob was willing to work 7 years for Rachel's hand in marriage, because she had not quite reached 20 years old, yet. We do not know, because it does not say. Genesis 29:18 says, "And Jacob loved Rachel; and said, I will serve thee seven years for Rachel thy younger daughter."
No, Jacob was dumb.
Jacob tried to buy Rachel with hard work from his part, that was a stupid move.
Are you saying that Jacob fell in love with a child?
In those years, societies knew more about biology than today. If the "girl" started to have her period, then she was already a woman capable of having children. Biology 101.
The idea of Jacob working hard waiting for a child girl to grow up and marry her, excuse me but such idea sounds funny, if not ridiculous.
The most important decision of life is salvation and then serving the Lord. The next most important decision would be marriage. It is hard to imagine that God would condone the marrying of girls under the age of 20, when He considers that the age when He holds people accountable for their life decisions. After watching young people grow up and leave home, I would never encourage young people to marry before the age of 20 years old. I have seen some young people greatly change after they graduate from school. It is good to wait a few years and see what direction they are really going to choose in life.
Your views are from the 21st century modern era, the biblical records are from the 1st century and before.
In those times, women didn't make the decisions.
Who knows if Leah, the older sister, ever loved Jacob, but she was his wife. As a daughter, she obeyed her father to lie with him and be his wife, she didn't obey her heart and less, she didn't make "decisions" about it.
In those years there weren't elementary school. high school, etc.
The expected longevity was 100 plus years, but what killed more people were diseases, infections, etc. Many died because savage animals, wars, etc.
Today, the expected longevity is 80 years plus, and more percent of people make it, not because we are stronger than those men in the past but because we have antibiotics, medicines, surgery, etc, which will help us to live longer. If those men in the past had our current technology to help our health status, the majority of them should have lived easily 120 years plus.
Starting families in great numbers was necessary because farm was the primary source of living, and after any infection because a dead body in the pound or accidents when working, etc. the need of starting families when young was recommended.
Today, having you living in the city sending children to school, you can't see your son marrying at the age of 20, neither your daughter, you will recommend for them to obtain a career, finishing university, finding a job, travel, and later to get married.
That is you in today's world.
That was not Abraham or Jacob or the mother of Jesus in those past centuries.
Based upon the fact that God holds young adults accountable from 20 years old and up, God would have never put such an important decision before Mary, as to whether she would be willing to bear the Messiah, unless she was at least 20 years old. God does not violate His own principles. Luke 1:34-38 says, "Then said Mary unto the angel, How shall this be, seeing I know not a man? And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God. And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. For with God nothing shall be impossible. And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word.
Your opinion is not based on any fact that biblical women were under the custom of 20 years of age for marriage.
That is your personal opinion based on your erroneous interpretation of the bible.
Mary could be 14 years old or, 20 years old or, 30 years old, and being a virgin. She could be 14 years old or, 20 years old or, 30 years old, and get married.