As elsewhere mentioned, our educational system often ties success to fast thinking. I've always known I am not a fast thinker and, in fact, had often been the slowest thinker in my classes. This made school difficult and I struggled accordingly. Ultimately, I offset this by studying harder than my peers. For me, it has never been about reading the material and repeating, for example, some mathematics system from memory, but in truly understanding that system.
I consider myself a deep thinker that can easily connect concepts, graph relationships, and see the big picture. This is why I prefer to work as an architect, on security projects, and inevitably play the right stocks on the market. I suppose, anecdotally, if I'm any model, that deep thinkers might be better suited to certain roles and might naturally gravitate toward them.
Finally, and now a bit off-topic: The fact that deep thinkers might be equated with "late-bloomers" might have to do less with "figuring out what they're good at", and more to do with a society and a system which is prejudiced against them. If deep-thinkers were better nurtured and led through the educational system, they may not spend their thirties, or even 40's, learning how and where to apply their talents.
There is a skill component to those things although. You could practice them a bit and improve your scores significantly. But is that really intelligence or just skill? It will always be a combination.
It is a detailed 900 page exploration if a lifetime of research from the famous behavioral economist Daniel Kahneman on the topic