If you ask a hundred people about their favorite literary character, then there's a high chance that you'll get young characters. What is wrong with older characters? Nothing. It depends on the reader. (Let's be more specific about the details. It depends on the age of the reader.) If you read too many books, then you notice something. The older characters are minor players in the story. It's not the case with High fantasy, but there's something else. Most books are written for the adult readers including the titles under Children's literature. For the older readers, it's recapturing their lost youth. They can also relate to their literary counterpart. But let's be particular about something.
Which older character will you remember the most? Let's count to ten:
Professor Severus Snape. He teaches Potions at Hogwarts, who didn't hide his hostility towards Harry Potter. It's not difficult to discern his need for affection, but there's more to his complex personality. He's been living in anguish for years, a result of lost love and guilt. He's also torn, as he can't decide which side to pledge his allegiance. There's a thing called double agent, but it's not an easy life. Professor Snape, a sarcastic figure, can be a lovable person. Yikes.
Lord Asriel. Anyone who read His Dark Materials will guess Lord Asriel to be in his late 40s. He has a fierce face and powerful shoulders, which reflect his sheer determination and willpower. He can be an intimidating figure, if not misunderstood by those who are afraid of the unknown. But look at him from a different angle. The world needs the likes of him. It comes down to motives, though.
Flora, Fauna, and Merryweather. They may have pure hearts, but their bumbling almost killed Princess Aurora. Let's not judge them.
Digory Kirke. He had a few appearances in "The Lion, the Witch and the Wardrobe", which would give the Pevensie siblings a wrong impression about the man. Readers would know better. What can they learn from such a person? Someone who says a few words may turn out to be the wisest. And gentle.
Gandalf. He can be the modern-day version of your hip grandfather, whom you're not ashamed to introduce to your (young) friends. He can be naughty when the situation arises, but his loyalty is his most admirable trait. He remembers his friends without abandoning them when they need him. You must have read "The Hobbit" to know it.
Atticus Finch. He may not be the coolest father, but Scout would think otherwise. And she turns out to be right at all. Mr. Finch is an honorable person, whom everyone will look up to. He has a just disposition, which is not an easy thing to do in the South. Doing the right thing can be a difficult thing to do, but this didn't discourage Mr. Finch.
Sherlock Holmes. You'll be a fool to assume that Holmes is a young chap. Otherwise, he might not be the brightest gentleman in London. Experience does count for something.
Don Quixote and Sancho Panza. They may be a pair of fools, but think again. They may be the most enlightened figures in a disenchanted land. Miguel de Cervantes's classic may be set during the final years of the Medieval period, but it doesn't seem different from the modern era. Some truths are universal.
Miss Jean Brodie. She may be faulted for her misguided views on romanticism, but this is the only way to inspire the youngsters. In her case, there are hints of bitter memories (on her failed relationships). It shouldn't be the case, but readers would figure out her finer traits.
Miss Marple. She seemed like a frail figure, but looks could be deceiving. She may turn out to be your doting grandmother.
Do you have a different list? Share it with us.