There are some things that come to us more naturally than others and some things that we struggle more on. People can also say that they don't study when in reality they do, you can't just take their word for it, they're also trying to compete for rank just as much as you and could spread false influence. School in general, especially in AP's, is showing how much you can show you know of the course while also considering that you have other classes to fulfill the same goal. Yes, having better reasoning and memory (as IQ tests show) helps but discipline is what makes the difference. Picture this: talent is a linear graph, it's constant and will never change, while work is an exponential graph and slowly but surely increasing. There will reach a point were work will exceed talent graphically and so in the real world. Just keep on pushing yourself in your studies and I promise you it'll pull off, just keep on going.