I am biased but for me c# (sharp) is a really good place to start.
You can create mobile, web and desktop apps using one or many of its libs and its relatively easy to pick up. It takes a little bit of time to get used to, but once how the ‘syntax’ works everything just falls into place.
I may get some hate from people saying “why not start with php” and I say this, php has a way of teaching newcomers “lazy” ways to program and once (if they do) ever migrate over to a stricter language they are going to have a really hard time adjusting. However, going from a strict language (like c#) to php is MUCH simpler.
Google c# ebooks and you’ll get a lot of resources to get you started.
The twitch API isn’t really something to dive into until you’ve managed to make something in a language already. Although for more seasoned programmers understanding the API is easy, for a newcomer it can be daunting to understand.
So for me, here is my suggestions:
Read up on your programming language of choice (c#, c++, php, python, even mirc.) and get to making a smaller project.
Read up on OOP programming “ideologies”
Read up on good programming habits and bad.
Read up on json <- what the twitch api really is.
How to process it and handle the data.
Once you’ve done the above you’ll have a solid understanding of the language you’re using, how to structure and program effectively (no matter what the language choice) and lastly how to access the api and use the data you scrape from the servers.
There is a lot more to it like sockets, http requests and headers and more complicated stuff like that. But get your basic understanding of your langauge and move up from there. Get a good book on your langauge and just work through it. This way you don’t get bored, don’t get frustrated by it not working because you’ve done a simple mistake like a missing ‘)’ or ‘;’ and understand what exceptions (you’ll understand why once you start working with the api).
You’ll get there - Just stick at it. Programming isn’t for everybody, requires dedication and the love of it. Constantly educating yourself as the landscape changes, new libs come out. Stuff like that. But stick at it. It becomes really really entertaining to see people using something you’ve made work flawlessly - maybe even make a little money from it.
Hope this helped. Best of luck 
Edit: and remember, google is every programmers best friend
