Some are still arguing that Luffy’s growth has happened too quickly. Let’s put this hypothesis to the test.
Luffy’s ambitious journey started when he was really young. Garp — one of the greatest and strongest marines ever — toughen him, giving him the tools early to be a survivor.
Then Luffy had a great role model in Shanks. Through Shanks, Luffy acquired his moral compass as a pirate. He learned the value of being a true friend and a man of action. Most importantly, he learned that you have to be willing to make sacrifices for what you believe in.
Later, Luffy put his survival skills to the test alongside his brothers. He practically raised himself by living by his own standards.
By the time Luffy started his journey at 17, our boy was no regular 17 year old. He had lived and experienced more than most young men his age. Hiding behind those cheeky smiles and the dumb and naive looks was a young boy who had been living like a grown man since he was a child.
Just like Oden, Luffy had experienced more at a young age than a lot of people have in their lifetimes. But as great as they were, they only became legends by going on their respective voyages.
Notice how Oda made sure to let us know which way the wind was blowing in in LogueTown. Luffy’s journey to the west ala Sun Wukong is a journey toward completeness.
During the first leg of his journey, Luffy spent months fighting through adversity, learning and adapting as well as experiencing defeats and failures.
After his failure, he spent 2 years training in the wilderness with the Pirate King’s right hand in order to grow stronger.
During the second leg of his journey Luffy fought even harder against even greater foes, mastering new forms and advance techniques.
Luffy’s journey has been hard and exceptional. So his growth isn’t all that surprising nor is it an ass-pull. People who make that claim have simply misread the story.