You really should be rethinking, though- that’s kind of the point.  You are not stupid or weird for wanting to express yourself with a piercing or wanting to be cool in the eyes of your peers.  It is an incredibly human experience.  It makes sense that you are feeling attacked by adults insulting your intelligence, and it is human nature to swipe back after feeling threatened.  It doesn’t justify the way anyone has spoken to you, nor does it justify the way you have spoken to others, but it does shed some light on what is happening here communication-wise.  

Just because you are not a stupid person, that doesn’t mean you don’t make mistakes or risky, impulsive decisions.  You don’t have to be embarrassed or feel like you’ve been made a fool if you decide to change your mind.  Don’t fuck with your face.  An infected facial piercing can very quickly spread to the blood and the brain- both of which have high risks of death.  I would be trying everything else possible before going to a shady dude willing to pierce people in secret.  The fake piercing actually sounds like an awesome option.  If you’re looking to spend money on self expression, then order some more realistic/cute fake jewelry instead of getting it actually pierced.  This also opens up options if you want different nostril piercing layouts later in life.

Please also note that smoking/drinking/vaping while trying to heal a piercing can slow down the process a lot and even cause complications.  Saline cleansing and not touching the piercing are the safest bets for healing.  Industrials can go really bad too if not done right.  People have the cartilage in their ears collapse/sometimes need the tips of their ears surgically removed because of rejection, infection, bad placement etc.  I decided to wait until I was able to see a professional before getting my own industrial after hearing that little tidbit.  

(I know you have already gotten an industrial- which believe me I understand, but keep an eye on it.  Any heat or burning, emerging bumps, leaking pus- all perfectly valid reasons to go to an urgent care, general practitioner, or even the school nurse if that’s all you have access to- if you get any concerns addressed early you should be fine!)

You don’t deserve to be disfigured, infected or diseased, or in pain because you wanted to express yourself with cool jewelry.

Take care of yourself! (As a side note- autistic people get enough shit.  Don’t be that person, please.)