The Lory says, “I am older than you, and must know better,” in the midst of a polite argument with Alice. That means that it's not the most politest way to it, but it's also not particularly rude. Some other ways of saying the same thing, in decreasing degrees of politeness: "If you'll forgive me for mentioning it, I may be a little older than you are, and have slightly more benefit of knowledge and experience." "I believe I'm older than you are, and so I stand good chance of knowing better." "I'm older, and I think I know better." <= this is about the same level as the Lory's sentence. "I'm older than you, and I know better." "I'm older and know better, so shut up, kid." Implying that someone is very young or very old, can be perceived as an insult, and so it's polite to use a little delicacy: "Elaine, I think you might be a little younger/older than I am..." "You might be old enough to remember.../you might be young enough to still be..." It used to be a convention that one should never asked a lady her age, but that has faded since "marriageability" is no longer so important to a woman's social status. Still, if you need to ask anyone - woman or man - their age, it's good to be polite about it: "May I ask your age?" "If you don't mind my asking, how old are you?" (Note: you said nothing wrong, and there's no reason for anyone to be offended.)

Thanks for your help!😄

It depends on how to use this word. In some cases, it is offensive while it does not happen all the time., so just be caution when you use it.