It's not necessarily too early, but teaching her to 'read' may not be the way people think. Children first learn about literacy and 'reading' just through play. They see you read and learn that print has meaning. She learns stories by rote, and pretends to read. She learns about sounds, phonetics and letters. She'll learn to recognise letters in her name, your name, other simple words. She'll learn to model it from you and other adults in her life. If she's exposed to it she will learn it. 3ish is a good time to start, but not to really focus on it. Make it fun. Show her numbers, clocks, letters and print. If she's interested go with her ques. Have fun with it.
HTH