Firstly: Doooo it! Do it do it do it and don’t let anyone stop you.
Secondly: Take as many physics classes as are available to you. And Chemistry and Biology too because cross-disciplinary study is a vast and interesting field right now. This advice goes for all genders, btw. You want to find out if this is something you are truly interested in studying full-time. High school physics and college physics are handled differently, but learning the material can give you an idea of whether or not you want to do a degree in the sciences or be an enthusiast in your free time. Both are cool.
Thirdly: And this is the advice specifically for girls*. You might come up against some adversity. I cannot fathom why but there are certain people out there who think girls are not suited to science. For reasons best known only to themselves. They are wrong.
Some people are not suited to studying science. They might not have the required mix of curiosity/creativity/logical thinking that all good scientists have. But the people who are not suited and the genitals they have are in no way correlated. The only constraint comes from society. Now there is a huge amount of history and (un)reasoning surrounding why society seems to discourage women from entering STEM (and most especially Physics) careers that we could literally devote an entire sister blog to just discussing and debunking these issues. But for now lets just say that anything anyone could say to you is either not true or not necessarily applicable to you. You know yourself best. So don’t let the nay-sayers bring you down.
Fourth and finally: Back to general advice; something that every person I have ever known who is studying anything in the sciences, my whole Physics class, my whole Theoretical Physics class, all my Post grad colleagues, has been asked is “Oh! And what are you going to do with that?” usually followed by the prompt “Teach?”. I recently advise someone that the correct answer to such a stupid question is “Whatever I want to.”
Take it one step at a time.
That is my overarching advice. For now you should take some classes and read pop science books like Surely You’re Joking Mr Feynman, etc. Next you get into college and major in whatever science strikes your fancy most *cough* Physics *cough*. Then you see about postgraduate opportunities then jobs then careers.
And don’t sweat it. You might find yourself at some point, for whatever reason, not doing science. But whatever you are doing, you can bring that natural spark and whatever level of scientific education you have to it and enhance what you are doing. Ask Alfred Hitchcock, Bill Nye, Lisa Kudrow, Mayim Bialik, Rowan Atkinson, Cindy Crawford, Natalie Portman, etc, etc, and so forth.
I hope this is helpful and I am sorry that it does not have any pictures.
*or, you know, other genders that are facing adversity when it comes to their dream of studying or having a career in science. The fuck do I know about your life?