I have this idea for an app that I'd like to make that provides a very simple service (or at least I believe it does), and essentially, I'd like to know what YOU GUYS think would be the quickest way to develop this application that I have in mind.
I know quite a bit about the whole programming and app development world, and I am currently in an AP Computer Science course. I'm fully aware of that thought that it may be best to just finish the course and then utilize the knowledge and experience I gained from it to start developing this app (which I may just end up doing anyways).
Regardless, I would still like to know what you guys think may be the best way for someone to create an application, when they've an idea and want to bring it into the world as fast as possible.
Depending on what it is, you might start by building a web-only app. If it's something you need to be desktop/laptop/mobile/tablet friendly all at once, I'd investigate LAMP stacks and maybe build your app in PHP. I do recommend using a good solid "base design" for your UI so it stays consistent. A fairly well-built CSS framework is awesome for things like this; I use MaterializeCSS for most things but you can use other things as well. I've heard good things about SemanticUI but I found Materialize to fit my needs better.
If it's a native app for a mobile device I can't really provide any advice, never done one before, sorry!
No problem. I wouldn't "go big" right out of the gate, I'd start small and have it free/ad-supported or very cheap one-time fee, then grow as you need to. That way you only have what you need, nothing else. Investing in infrastructure and servers and whatnot that's more than you need sucks; I've done it once and I will never just go rent a server for the heck of it again.
Unless you need like GPU or off grid form factors, I would guess you could pretty much facilitate anything with a web app. Some graphics or interactive, game play stuff is going to be best served with native OS, but you can do a lot with the browser, and likely your going to need a back end if your app is at all a service.
Set up a Linux server at home for testing and development, then rent a VPS from Digital Ocean or Linode or somewhere like that only after you're sure the app is ready to "go public". No sense paying for a remote server if you're only developing on it.