I am 21 as well, and I don't usually talk about carrying firearms with people in most of my classes unless it is a criminal justice course. I have noticed the same thing you are noticing, I saw a picture of a billboard saying something like " I carry a gun because I can't carry a police officer". I have met some people(including the cute girl that cuts my hair at supercuts, though she is a little bit older) that like to shoot. That said the people I speak to that don't, aren't necessarily anti gun or brain washed, they are just afraid of them because the have 0 experience with them. I would say few of the people that I come into contact with that the conversation topic is firearms are anti gun.
It's better to be judged by 12 than carried by 6.
"No freeman shall ever be debarred the use of arms." --Thomas Jefferson
"Age is an issue of mind over matter. If you don't mind, it doesn't matter."