I've been in situations before where adults have judged me and discriminated on me for being a teen - automatically deeming me a teen rebel who's irresponsible and not to be trusted. What should a teen do in this situation?
Thank you for your inquiry. I'll admit this all sounds pretty familiar. I've been in your shoes one too many times, and I know how you feel. I think as teenagers, we've got to own that our reputation precedes us. It's not ideal, but it's often the case, and the best thing we can do is to prove to ourselves that those who have misjudged us are wrong. A lot of people feel that they shouldn't have to prove anything to anyone, but while others may not deserve it, you do.
Age can, in my opinion, be a temporary disability, but that doesn't mean that we can't fight to overcome it. The best way to demonstrate your maturity is to never be deterred. It's easier said than done, that's true, and it honestly depends on who you refer to when you say "adults," but regardless of whether they're the people closest to you or whether they're just acquaintances and strangers, try to look to the peers and adults that do value you. I know they exist. I found mine in my parents, my teachers, and even people I've met in passing, and they've all inspired me in their own ways.
No matter what you do, always, always try to be the version of yourself that you can be proud of. And if you're openminded, a little bit of self-assessment never hurts. Even when you haven't done anything wrong, there are always opportunities to grow as a person. Try not to give those adults that you speak of the confirmation they're looking for. Surprise them with your class and self-command. Who says teenagers can't have poise?
I hope that I've been able to help you in some small way. Remember, you deserve to be taken seriously, so don't let anyone take that away from you. I know that if I were in a situation like the one you've described, I'd smile when people expect me to cringe and appear unaffected when they expect me to be oversensitive. That'll give 'em something to reconsider.
Whatever you decide, remember to put on your poker face. Brave the ridicule, but don't take it to heart. It doesn't matter who they think you are, and you won't always be able to change their minds, but I believe you know exactly who you are, and sometimes that's got to be enough.
Best of luck to you,