I REALLYYY want to become a fashion designer?

Well, what you don't want to do is "be just like Kira Plastinina - or anyone for that matter" - because you must create your own individual designs as a fashion designer! If you were to become just like someone else that would be "copying" and that's not only illegal, it's also not looked upon with any respect, and no one would ever want to hire you or buy your designs. So, first thing is to go to school for this - there are literally thousands of schools that have this program. Find one near you, and enroll. As you go through the program and begin to learn the principles of designing, you are expected to begin to develop your own "style" as you create. And there it is!