One day, a high summer flood washed him out of the burrow where he lived with his father and mother, and carried him, kicking and clucking, down a roadside ditch. (3)
The hero can't have his parents fighting his future battles for him now. And notice how he's "kicking" and "clucking" as he's swept away—it sounds like this is one mongoose who might not quite be ready to give up.
It is the hardest thing in the world to frighten a mongoose, because he is eaten up from nose to tail with curiosity. (7)
Curiosity killed the mongoose … or something. Rikki-tikki's youthful curiosity gets him into all sorts of trouble and shenanigans, like any young protagonist should. Naturally he'll learn to hone this curiosity as the story continues, but now we're getting ahead of ourselves.
He came down almost across her back, and if he had been an old mongoose he would have known that then was the time to break her back with one bite; but he was afraid of the terrible lashing return-stroke of the cobra. (30)
You know how your parents tell you to learn from your mistakes? Every coming-of-age story ever written agrees with them. (See? You have to make them.)
Rikki-tikki knew he was a young mongoose, and it made him all the more pleased to think that he had managed to escape a blow from behind. (33)
The sweet, sweet smell of victory. This one is a great confidence booster for our protagonist, and he's going to need it: the difficulty is about to get cranked up to eleven.
If Rikki-tikki had only known, he was doing a much more dangerous thing than fighting Nag, for Karait is so small, and can turn so quickly, […]. (35)
The problem with being a kid (or a young mongoose) is that you don't always know what you're getting into. Rikki-tikki is lucky he survived this one. It's easy to be brave if you don't know what you're up against.
That night at dinner, walking to and fro among the wineglasses on the table, he could have stuffed himself three times over with nice things; but he remembered Nag and Nagaina, […]. (38)
If knowing when to stuff yourself and when to refrain is a sign of maturity, then we revert to childhood every holiday season. (And every time Ben & Jerry's comes out with a new flavor.)
[Rikki-tikki] looked at the thickness of the neck below the hood, but that was too much for him; and a bite near the tail would only make Nag savage. (59)
More signs of Rikki-tikki's maturity. Unlike his battle with Karait, the mongoose actually takes the time to assess the situation and plan an attack. Someone put this guy at the head of a military, quick.
"On the rubbish-heap by the stables, mourning for Nag. Great is Rikki-tikki with the white teeth."
"Bother my white teeth! Have you ever heard where she keeps her eggs?" (72-73)
Yet more signs of maturity? It's almost like Rikki-tikki is growing up before our eyes! Here, Rikki-tikki rejects Darzee's praise, since he knows Nagaina is still alive and deadly. There'll be time to post on his Facebook wall after the final battle is won.
Rikki-tikki put his paws one on each side of the egg, and his eyes were blood-red. "What price for a snake's egg? For a young cobra? […]." (94)
Rikki-tikki is a thinker as a much as fighter now, as all the lessons learned come to this final battle with Nagaina. (But we're still not quite sure how to feel about all the destroyed eggs.)
Rikki-tikki had a right to be proud of himself; but he did not grow too proud, and he kept that garden as a mongoose should keep it, with tooth and jump and spring and bite, till never a cobra dared show its head inside the walls. (111)
Rikki-tikki doesn't get too complacent in his big-boy boots. He maintains a diligence that proves he's come into a true maturity. Good for him!