More references of where this sort of thing is promoted:
*** w02 5/1 p. 28 Implanting Love for Jehovah in Our Children’s Hearts ***
We were touched when Hans Werner got baptized at the age of ten.
*** w95 2/15 p. 24 Dominican Republic—Still Open to Discovery ***
For example, Tamar and her sister Keila were both baptized at the age of 10 and entered the full-time pioneer ministry by 11.
*** Watchtower 1992 March 1 p.27 ***
“In the summer of 1946, I was baptized at the international convention in Cleveland, Ohio. Although I was only six years of age, I was determined to fulfill my dedication to Jehovah. That summer I served as a pioneer for the first time.”
*** g71 4/8 p. 23 - Christian Togetherness in Brazil
In Goiânia, a girl eleven years old was among the seventy-seven baptized
*** yb02 p. 110
Curaçao ***They started to study with Jehovah’s Witnesses. Subsequently, Renzo’s father and mother along with one of Renzo’s Bible students were baptized. Renzo, now eight years old, was baptized at a circuit assembly in Bonaire.
*** w96 10/15 p. 32
"Jehovah Answered My Prayers!" ***Consider, for example, a boy named Joel. He symbolized his dedication to Jehovah and was baptized at nine years of age
*** w90 7/1 p. 11
Jehovah’s Blessing Has Made Me Rich ***When I was nine years old, I determined to dedicate my life to Jehovah and be baptized. Because of the persecution, we were not told the location of the meeting, but we were led to a place in the forest where a large group of Witnesses were enjoying a "picnic." There my older sister Eleanor and I were among the many who were baptized in the cold waters of a nearby lake.
*** w92 10/1 p. 22
‘Should I Get Baptized?’ ***Ayumi got baptized when she was ten years old.
*** w87 4/15 p. 13 par. 15 Gaining Peace With God Through Dedication and Baptism ***
In modern times, a Christian named Jean was baptized when she was only ten years old