Aging with Respect

"Respect your elders" - I've always lived by this rule since I was little and never talked back to, doubted, or argued with the adults and elders in my life because I always thought they knew best solely because of their age. But now, whether it's because I feel more rebellious as a teenager or because I know more at 16 years old compared to at 2 years old, I don't agree with this adage.

I will respect who deserves to be respected: to me it has nothing to do with age since it's just a number. Granted, generally speaking the more elderly have more wisdom due to accumulated experiences from the past, but I have encountered adults in my life who, despite this alleged experience, have shown me that they don't deserve the credit and respect they are oftentimes given: as 50 year old people, they act as immature and as irresponsible as 5 years old - if that's the case, what gives them the right to be held in a hallowed light?

Age to me is arbitrary: the only thing that someone's age indicates to me is his/her number of years on this earth. It does not show me the qualify of life, the true wisdom, or the deserved respect - I see these as I grow closer to that person and learn more about him/her. You don't know a person's history, personality, or maturity just by taking one glance at him/her; if that's the case, why are we allowing ourselves to do so with respect and age?