Does our eyeball increase in size as we grow?
First of all, I should quote the sentence from the MOST reliable ophthalmology sourcing in the world - American Academy of Ophthalmology:

Section 11 - "Lens and Cataract"

"The equatorial diameter of the unfixed human lens measures 2 mm at 12 weeks and 6 mm at 35 weeks. Both the growth and the maturation of lenticular fibers continue throughout life." The antero-posterior dimensions of the lens enlarge from 3 mm at infancy to 6 and even more in adult years.

"The lens continues to grow throughout life (page 7 the same source)

Secondly, the growth of the eye continues after birth - at the beginning the growth is fast and later the growth is much slower but still - there is GROWTH of the eye after the birth.