Eh! You not one of my former students right? ;-)
I also get stopped when entering exam halls when I have to invigilate exams. Bloody security guards think I'm a student and won't allow me in with my bag. lol. Happens all the time. Bloody security guards, the hokkien peng types, poor chaps never knew the flower power generation. And I actually have to push them away to let myself into the examination hall! The last time, when I got in, even the other lecturers thought I was a student!
Thank goodness my faculty's office rep was there to intervene. Because I was pretty worked up after some drinks and no sleep for the past 36 hours!!!!!
I just want to add that other than being yourself, take note that you have to earn a living some day. Live on your own. Pay your bills. Wash your clothes. Do the drill, IOW. There's a time to have fun as you grow up, with music (and its culture) being one of your close friends. But someday, you'll have to stand on your own and be counted for.
There's a reason for everything, even the bad. As much as the good. You can't be right all the time. Someday, you will be yourself, and chances of that happening usually happens after you're 21. So, don't take things too harshly, especially if you're doing what you want, as a teenager or a young adult.
Because, in true life, you never ever get to do what you want, all the time. There are very few rockstars in the world. I don't know of one in Singapore. So chill, have fun. And enjoy yourselves but don't take things too seriously and stay off cheap drugs.
When you start paying your own bills, then that is day when you truly become yourself. Give yourself time. Because that day will come. Just don't be surprised who you turn out to be.