Bilbo has greatly changed by the end of the book. He has had many experiences which forced him to mature and grow up. Living his boring Hobbit lifestyle, he would never have been able to mature. The adventure forced him to mature, because if he didn't he would never have been able to survive through all the challenges that he and the dwarves faced. By the end of the novel, he was more like Gandalf than he was the old Bilbo. Gandalf was the one thing that the dwarves could depend on. If there was a problem, he would always help them. But eventually, he was forced to let the group fend for themselves. He had to do this because, otherwise, Bilbo would never mature. The main reason that Bilbowa invited to come along on the adventure was so that he could mature. Not all hobbits have a chance to mature, but Bilbo was chosen because he was part Tookish, so he had an adventurous quality. IN order to fulfill it, he needed to exercise his Tookish side by going on this adventure. When Gandalf left, someome had to fill his roll so Bilbo stepped in. At first, he had no self-confidence, so the dwarves didn't have any confidence in him. But as he performed more and more heroic acts, he began to gain some self-confidence. By the end of the adventure, he had all the confidence in the world. The dwarwes respected him because he finally believed in himself.
Bilbo steadily matured throughout the adventure, but there were a few points that proved how much he had grown. When he found the ring, it gave him power. He was smart enough to use the power wisely, to save the lives of the dwarves and himself. When he killed the spider, it also showed his growth. It was the first time he had ever killed anything, so he had crossed the line. After that, he was able to kill anything. It gave him the confidence to feel that he was able to kill Smaug. The most important point in his maturation process was when he gave the Arkenstone to Thorin's enemies. It shows how rastional Bilbo is, and even though it may have seemed like an act of insanity on Bilbo's part, it stopped many deaths. It shows how he learned to think for himself, and no one can influence him to do anything that he doesn't think is right.
In many mythological stories, a dragon represents greed. Smaug had mounds of treasure that he never used, yet one missing cup from his mounds caused him to be extremely upset. When the dragon is killed and Thorin takes over the palace, he is overocme wiht greed. There is plenty of treasure foe everyone, but he refuses to share it. Greed causes people to be illogical and irrational. Thorin will not make any negotiations or compromises, because he has been put under the dragon's spell. At one point, Bilbo almost falls under the spell. He fears that he will not get his share of the treasure, so he gives it to Bard, who deserves it more than because he killed Smaug. Bilbo's wise and selfless choices show how much the adventure has helped him to mature.