I noticed my DD was teaching herself to read and write letters (no correct spelling, except her name and copied words) at three. When other parents pointed out that it was unusual that she was the only toddler drawing rainbows with sidewalk chalk in ROYGBIV order, I started to feel as if I had to do more for her. I didn't want her "schooled," however. I enrolled her in a half-day, five-day a week Montessori pre-school with the understanding that she would continue the following year into full-day kindergarten at 4. This allowed her to PLAY, explore, and learn what she was interested in without being in an academic, curriculum-driven environment. It was the best choice for her. Listen to the advice given here, and follow your gut.