The second twin emerged differently. Targum Pseudo-Jonathan on Genesis 25:26 gives the detail plainly: "Afterward came forth his brother, and his hand had hold on the heel of Esau. And they called his name Jakob (Yaakov). And Isaac was a son of sixty years when he begat them."
The name Yaakov comes from akev, heel. But the sages heard more in it. The root also carries ikvah — following, coming after, grasping at something just out of reach. Jacob's name is a verb. He was named for what he was doing at the moment of birth: not arriving first, but refusing to let the first leave him behind.
Consider the image. His brother is already in the world, already named for completeness. And Jacob, the younger, will not release the heel. It is the first picture of the struggle that will shape his entire life — wrestling with Esau, wrestling with Laban, wrestling with the angel at Peniel, wrestling with himself over the birthright, the blessing, the burial.
Isaac was sixty years old. Twenty years after the wedding. Twenty years of Rebekah's barrenness, of prayer on Moriah, of waiting. The Targum notes the number with quiet respect. The patriarchs were not impatient men. They waited decades for what they could not force.
Here is the teaching. Jacob teaches us that you do not need to be born first to become the one who carries the blessing. You only need to refuse to let go. He comes out of the womb already practicing the discipline he will practice his whole life: holding on. When the angel wrestles him at the Jabbok decades later (Genesis 32), Jacob will say, "I will not let Thee go, except Thou bless me." He learned that grip in the womb.