How long did it take to teach Doodle to walk in "The Scarlet Ibis"?

Doodle may have been slow but he was certainly persistent.
He first began to move around a bit when he was two years old and finally began to crawl
(albeit backwards) when he was three. He still couldn't walk at the age of five (most
children learn to walk between the ages of nine and fourteen months), so his big brother
set out to teach him. The exact time is not specified, but big brother began working
with Doodle in the spring and, after "many weeks," he finally took his first steps. They
decided to keep working and finally displayed Doodle's new talent on his sixth birthday,
October 8th. So, the two boys may have worked together for as long as six months before
springing their surprise on the unsuspecting family.