First, 16 is still pretty young. Second, just because you didn't have STEM hobbies when you were young doesn't mean you weren't given the framework to excel at STEM. It's not "you learn math or you don't", rather the argument is "you develop the framework for mathematical thinking or you don't".

For what it's worth I also did better with literature and history than math when I was young. Also, I struggled to pass Calculus 2 but breezed through upper level CS courses. It's a very fuzzy thing.