As others have said, there's no "right" reading speed. Whatever speed you read at is the best for you.
I suspect I'm a pretty slow reader. I average about a book every 5 days or so. Normal sized novels, around 400-500 pages (at least I think that's about a normal sized novel?). Plenty here probably read 2 or 3 a week, and there are others that might take a couple weeks to read one. Then there are binge readers like my wife, she'll go weeks without reading and then go through 10 books in two weeks! There's no right or wrong way to do it.