I didn't seriously start reading books until I was 18 years old. Found that one that piqued my interesting (Across the Nightingale Floor) and now I have a huge library of books. I don't like reading thrillers, I don't particularly enjoy anything set in the modern age - unless it's set in a faraway country and/or a different time period. That I least I feel like I learn something from.
I tremendously enjoy reading historic books. Fairly sure they outweigh the novels. I loved S.P.Q.R. by Mary Beard. She didn't just tell the story of the Roman Empire, but presented and explained why certain source aren't necessarily reliable, why such and such was inevitable and probable, the significance of events and characters in the empire's story. Another, Genghis Ghan by Frank McClynn was also fantastic. There's a lot of books to chose from, and I felt like I picked the right one. It's a big book, and I have too little brain capacity to remember the details or even all his victories and accomplishments, but I'll always remember his three best generals: Jebe, Subutai and Muqali.
When reading history books (and most of the time) I enjoy reading two at the time, shifting from one to the other at major points as to not to get bored. Not that they're boring, but both of the books I'm reading are 900-page long, and they take a while, and I need a break from one topic for a while. Currently I'm reading Napoleon The Great by Andrew Roberts. It's fairly straightforward in telling his entire life, so I wouldn't recommend it unless you're absolutely interested. The other is A People's Strategy - The Russian Revolution by Orlando Figes. I don't live in Russia but I'm Russian, and this particular point in time interests me.