When is it time to start working on reading skills? Right now. Reading begins with vocabulary, oral language, and talk. So talk with your child often. Talk and listen, share family stories, use new words, ask open-ended questions, be patient, and encourage word use.
The most fundamental definition of reading is being able to interpret written symbols and understand printed material. Like walking and talking, learning to read does not happen all at once, but happens gradually through continuous experiences with printed material and reading related activities.