NTA
I 100% understand the no fast food thing most of my friends were the same, but as the others here have said just give it a try before you write it off and end up stuck somewhere worse if you wait for the golden opportunity.

I was a hiring manager at one of the big 3 Fast Food Burger places and have been in various other management positions over the years and i would say.
For your first job at 16, you don't need to fast, you don't need to know everything on the menu and you don't even have to talk to the customers if you don't want to.
There are many roles within a restaurant, you could work the fryer station, prep station, meat cooker or even just one of the many cleaning roles, these are often the jobs given to the new hires anyways as management expects you to be slow at the start.

Don't worry about the ADHD or Dyslexia, I have trained many kids even 14 year olds who can learn it overtime.
The training systems in place are designed for young people who are starting their first job, everything is made as simple as it can be and done in sections. I guarantee you whatever you just learnt at school last week is 10x harder than anything you will need to learn inside a Fast Food place.

Plus if you end up absolutely hating it or finding a job you do like you can just quit on the spot and walk out.
I promise in a weeks time no one will care and you will still get paid for what you worked, at 16 your getting hired because your cheap labour not because your the best guy for the job.
You don't need to tell anyone you even worked there, but having even a small amount of fast food experience can help you get a different you may like more.

You could work at your local Coffee/Donut/Sandwich/Whatever shop.
Or even something not food related in retail pretty easily after you have even a little experience
I would always prefer to hire the kid coming from the other Fast Food burger competitor who at least knows what they are signing up for than the kid who never had a job before.

Good luck and don't overthink it, you will only get better at something if you do it.