A.S.
Get the 12". I started both of my kids on 12" and they now love bike riding. They were very confided riding a bike that fits them, not one too big. We had kids the same age in the neighborhood riding bigger bikes, they were scared of them. My girls moved up to the 16" at 4 or 5, but went back to the 12" to learn to ride without training wheels. Get the Dora the Explorer she will love it. Reviews are written by lovers and haters. The average person doesn't write them.