[analog31]

Start with realistic expectations. It will take longer for you, than for someone who's 9 years old. Find sources of large amounts of written material that is nonetheless fairly simplistic, but at the same time not children's songs. There's a lot of sheet music at IMSLP.

An example is the Mikrokosmos collection by Bartok, written as a method book for kids, but is nonetheless serious music.

Don't focus exclusively on reading. When you've worn out a piece from the standpoint of reading, continue practicing it to build technique and musicianship. All of those things develop together. Good luck!