Is normal to be a really slow reader?

I really like to read, but my slowness keeps me from reading more because I usually lose interest in whatever book I'm reading since I takes me so damn long to finish it. So yesterday I finished this book called The Fault in our Stars and it took me roughly 14 hours to read HALF of the book. I see people in the internet saying they read this same book, the WHOLE thing, in 8 hours. And some even say they finished it in 4 HOURS. Oh, and I must say I'm not a native English speaker and I was reading in English but as you can see, my command of this language is fairly good, so it shouldn't have taken me so much longer to finish the freaking book.