she.

Exodus 13:2
"Consecrate to Me every firstborn male. The firstborn from every womb among the Israelites belongs to Me, both of man and beast."

Exodus 22:29
You must not hold back offerings from your granaries or vats. You are to give Me the firstborn of your sons.

Luke 2:7
And she gave birth to her firstborn, a Son. She wrapped Him in swaddling cloths and laid Him in a manger, because there was no room for them in the inn.

Romans 8:29
For those God foreknew, He also predestined to be conformed to the image of His Son, so that He would be the firstborn among many brothers.

and he.

Luke 2:21
When the eight days until His circumcision had passed, He was named Jesus, the name the angel had given Him before He had been conceived.