[ChuckMcM]

Why choose? Its not like its not possible to understand the full stack and you've not even gotten to and age where most folks would be starting college. Work through the various web frameworks (Bootstrap, Node, Django, Rails, ...), then look at the API systems that people have setup, then move on to Varnish / Nginx / Apache followed by CGI scripting, databases, and Python / Perl / Go / Java back ends. Should be able to get to all of that by the time you're 19 maybe 20. Follow what ever is the most fun / engaging / thrilling.

[orangethirty]

Like ChuckMcM, do/learn everything. Why? Because once you start learning you will realize how everything seems to look alike. For me front end is a lot like back end in terms of structure and organization. Messy code can exist in both sides. Plus setting up a server is no harder than learning a framework API, it just requires that you do it. That's it. I would also add that you go and learn some embedded stuff like the arduino. It will really open up your mind to hardware and allow you to understand what is behind the software. I started when I was very young (bit younger than you), and wasn't comfortable coding until years had passed. But once I reached a given point in skills I realized that there were no limits as to what I could build. You will achieve the same if you don't quit.

Good luck.