It took a lot of practice! Haha . I read my first book at 12, and my second at 16—and at the time it was incredibly hard to maintain concentration—but I wanted to do something creative with my life, so I persevered; taught myself how to enjoy reading a story essentially.
Plus, I have a dedicated antique chair in my library, which settles me comfortably into "reading mode".
I definitely don't regret it.
There's a lot of great literary gems that haven't made a smooth transition into a popular medium.