Being 17, I would assume you have a little free time (no disrespect, not calling you a kid). If doable, take the next two weeks to a month to practice on your own dummy site. Put a bunch of dummy content on it.
Some themes are bulky and have a ton of functionality, coming with a lot of plugins. Come up with a few core functionalities and purposes for this site. I'd make it so the site has to be dynamic. Learn where you can trim all the fat off.
Also, hosting in a way where you have access to the server will teach you a thing or two.
Pretend it's your money site that you want to bring in money by x date. Build, crash out the site, build, rinse, and repeat. Until you get to the point that the site works the way you wanted, and also has good optimization stats. Get to that point before "your x date."
If you can get a heavy site (Lots of Javascript, CSS, etc. required) to decent numbers, still working with the core concepts, you planned from the beginning. Within a few weeks, you should surely be able to get most local websites into the milliseconds quite easily.
You'll likely learn a lot more, having the freedom to make plenty of mistakes and crash the site to your heart's content.
After that, strategically offer your newfound skills pro bono to influential and well-rooted business owners in your community.
P.S. This "dummy site" can act as a real project/side project.
P.S. All of this is assuming that this is the path you choose to go down. I know the feeling of "I don't care what it is, as long as it works." If you throw enough "spaghetti" at the wall, something is bound to stick. You're in the right place to learn. Regardless if this is the "method" you choose or not, starting this dummy site will be beneficial. It'll help you think laterally, and in ways, you couldn't have before starting. Whether what you do now, next time, or the time after that is the successful one. Get the ball rolling. Seeing how things work with your own eyes, causes, and effects will help you understand the problems and solutions. PROBLEMS and SOLUTIONS.