Why does Baby Jesus Look like an Old Man in Medieval Religious Iconography?

When perusing the Medieval religious iconography in a museum, it is difficult to miss baby Jesus with the face of a grown man! Why was this his popular depiction?

Iconography – American Association of Iconographers

The Baptism of Christ

The Baptism of Christ in Art and Iconography

Saint Joseph, Spouse As Mousetrap - Ad Imaginem Dei

Nativity, Definition, History, Themes, & Facts

Why do babies in medieval paintings look like old men? - Quora

Why Medieval Art Weirdly Depicted Babies With Old Faces

Beasts. Animals in the medieval art of the MEV

New Christian Icons – American Association of Iconographers

Why babies in medieval paintings look like ugly old men - Vox

Your body is full of wounds': references, social contexts and uses