I figured you were "too young to carry".
Some officers think that they know the law and that it says that you have to be 21 to carry a handgun. They reason that you have to be old enough to buy a gun to carry it. Which is somewhat true. You, probably already know, can buy a handgun at the age of 18 or older, so you can carry it. I would carry the "youth handgun safety act" with me everywhere I go if I was you. This would be the law they're talking about when they say you're too young to carry, and it just says MINOR and a minor is under the age of 18.
Also, It is highly regarded to only carry in a shoulder holster if it holds your gun vertically. It is a bit unnerving to have a gun pointed at you, even if they don't have their finger anywhere near the trigger.
I really don't think you will have much, if any, people run from you just because you're carrying. A lot of people ask me something to the point of "Is that a real gun?", of course it isn't because that is dangerous. But just answer their questions politely if you wish. Try not to handle your gun unless it is necessary, if someone is getting too close to me for comfort (like in a checkout line) I just rest my elbow on my gun and turn so it is facing away from them.