Wow the OP is pretty much my thoughts as I exited high school. Congrats for having the courage to ask such a prickly question. As someone not much older than you, my advice may not be as time-tested as others' on this forum but, I am currently "approaching this problem", so here goes. Before reading the rest of this, I would first suggest looking up "impostor syndrome."
Throughout high school, one of my very close friends was a BEAST at math and physics. Although I considered myself above average, I felt like I just couldn't compare with her. When we would discuss solutions tests and competitions, I would always preface it with "well this reminded me of a problem..." and give a pretty standard approach whereas she would start with "oh, I noticed/felt/guessed/was told by the Virgin Mary..." (ok maybe not the last one) and come up with some of the most elegant methods I knew I would never have derived. In short, my approach relied almost entirely on my work and exposure to different things while hers seemingly came from her amazing intuition and spatial reasoning skills. And so, I threw myself blindly into chemistry, first because I absolutely enjoyed it but second because I thought I wasn't "good enough" for physics, and any of the small accomplishments I had were due to luck and my "beating the odds" temporarily. As if to confirm this, during senior year, this friend earned more than double my score on a national physics competition while breezing through a mechanics course that I struggled through. Believing that the law of large numbers would reveal my incompetence if I pushed enough, generally avoided physics outside of class. I entered college as a chemistry major. Things only got worse from there. I quickly found out first semester that what I enjoyed about chemistry was...physics and being surrounded by physics majors, rather than just my one friend in a public high school made everything seem so much sharper. Now as a physics major I was "behind" because these people had spent high school racking up experience and math background. Again, their approaches seemed to be divinely inspired, but this time I "knew" that I couldn't solve the problems on my own. My aspirations were shattered, and I just wanted undergrad to end so I could stop the deception and finally be "weeded out". The rest of freshman year passed in a blur of career fairs and alumni interviews about how easy it was to jump ship from physics into other quantitative pursuits.
So what changed? After a summer of off-campus research isolated from other undergrads, I realized that a physics major isn't something you win by being smarter than other people; it's something you earn based on your own effort. If I want to devote my time to studying physics during undergrad, then there's nothing else to it. Of the alumni who had left physics, not a single one regretted studying physics in undergrad rather than something preprofessional; they had the rest of their lives to think about their jobs. To this day, I'm unsure about whether it's industry or academia for me, but options are open and that's good enough for now. Finally, I finally learned how to deal with impostor syndrome: "fake it 'till you make it." Lie to yourself that you're smart enough. Tell yourself that you're as good as your peers. Once I stopped wasting precious brainspace on comparisons, I learned better and regained my enthusiasm for physics. In the end, those two "lies" became truths more or less.
You're smart enough to know what you want to study. And that's all the intelligence you need to study physics.
