You can omit me from any list of folks that think you are old and/or mature.
You are no doubt, a person of intelligence. Your ability to read, comprehend and regurgitate what you read in books and on the interwebz is remarkable, almost as remarkable as the level of your naivety and lack of real-world experience.
That is what is going to round you out.
I'm sure that you could write me a 3 page dissertation on shaving in the morning, including the pros and cons of doing it, the best time to do it complete with sources of reference. Invariably, your report would lack the voice of experience and would lose any credence with anyone that has read it the moment they lay eyes on you as it is obvious that you have never picked up a razor in your life.
You can tell us all about war and how horrible it is, yet you have never picked a weapon and stood a post. Until that time, you are unqualified to discuss the horrors of war.
Until you have walked the slums of Boston (or Philly if you choose to come down here) and handed out blankets to the less fortunate when it is so cold outside that you, yourself are freezing in your long johns and brand new North Face jacket that mommy and daddy bought for you, you know nothing about what less-fortunate means.
Nothing of which you claim to to be so knowledgeable about is worth a hill of beans. You claim to have knowledge of the difference between the homeless, bums, drug addicts and those that are lazy yet I am willing to bet that you have never walked anyplace close to where these people "live" unless it was on a field trip or you were chaperoned with parents, let alone have had one-on-one face time with any of them.
Mistake you for old? Hardly.
It is quite obvious how young you are by the rose-tinted, sunshine and puppies perspective that you put everything into that gives it away.
Until you have lived a little yourself and have tried to put your knowledge to use, in a practical, real-life scenario, you really do not have any clue about that which you speak of.
Don't believe everything you read in textbooks as gospel. Remember, it was not too long ago that textbooks still claimed that the Earth was the center of the universe...